National Archives catalogue number CAB 106/8.






Highland Light Infantry

Lancashire Fusiliers

Royal Engineers


Operation COLOSSUS


A narrative of the execution of the operation based on Information given by Lt. A.J. Deane-Drummond, Royal Signals.


Maps:  ITALY:  1/100,000 Sheet 186 - S. Angelo de' Lombardi.

            ITALY:  1/50,000 Sheets 186 - I - Andretta

                                                    187 - IV- Melfi.


The object of Operation COLOSSUS was the destruction of the aqueduct over the Tragino torrent near Calitri on the ankle of Italy.  This aqueduct was on the extensive pipe-line system known as the Acquedotto pugliese which taps the head-waters of the River Sele at Caposele, passes the water through the Apennines and supplies the province of Apulia.  It is from this system that Taranto, Brindisi and Bari draw their water; Taranto a Naval Base, and Brindisi and Bari, at the time the ports of shipment of troops and stores from Italy to Valona for the Greek campaign.  A serious interruption to the water supply would have dislocated work at these places and been of marked, though indirect, help to the Greeks in their fight in Albania.  (1 - See Appendix I)


The demolition parties were to be landed by parachute, to blow up the aqueduct and then make their way to the west coast at the mouth of the River Sele where they were to be picked up by a submarine.  The operation was to take place from Malta on 10th February, 1941 and the submarine was to be at the rendezvous five days later.  A small diversionary air raid over Calabria was to be made at the same time.  The party was trained in England and assembled in Malta.  Six Whitley Mark V Bomber Aircraft were specially fitted and flown out.  Each aircraft was to carry a subsection of an officer and five other ranks with arms, ammunition and explosive.  Major T.A.G. Pritchard, Royal Welch Fusiliers, was in command and Captain G.F.K. Daly, Royal Engineers, was to be in charge of the demolitions.


The aircraft left Malta at sunset on 10th February at about 6.30 p.m. and were due over the target at 9.30 p.m.  The moon was full and the journey was calm and uneventful except for slight anti-aircraft fire over Sicily.  The intention was to run up to the target from Calitri across the River Ofanto and to land the parties on hill 427 about half a mile north of the aqueduct.


At 9.42 p.m. the first aircraft flying at 400 feet above the ground dropped the men, arms and explosives from 50 up to 250 yards from the target, four others a quarters and three quarters of a mile away, short, between the River Ofanto and the aqueduct.  The first man to drop from Pritchard's plane landed farthest away from the aqueduct and came down on the pebbles in the river bed.  Two of these five aircraft failed to release the arms and explosives.  (1 - The men who came down from these aircraft said that the pilot light of the release circuit was not glowing and that repeated demands to the pilots to switch on the circuit produced no result.)


The sixth, with Captain Daly, did not land its subsection until two hours later and then some two miles away to the north-east in the next valley.


Lt. A.J. Deane-Drummond, Royal Signals, landed from the first aircraft about 50 yards from the aqueduct and in the light of the full moon saw at once that it was not guarded.  The aqueduct stretched below and in front of him across the steep little ravine of the Torrente Tragino, the bottom of which was covered with scrub and small trees; and led up to a small hill beyond.  Over the brow of this was a second aqueduct crossing another stream, the Fosse della Ginestra.  On his left the mountainside rose steeply with a group of farm buildings fifty feet above him.  Across the ravine to his right, a track led away from the farthest pier of the aqueduct, dipped over the hill in front, came into view again by some farm buildings on the other side of the Ginestra and ran along the slopes of the valley past the confluence of the two streams down towards the main road, the railway and the River Ofanto.  On a mountain top beyond the river twinkled the lights of Calitri.


In a few minutes Deane-Drummond's subsection was round him.  He sent two men to search the farm buildings above him and the other three to go to the farm across the ravine, with orders to bring back all the occupants to the aqueduct, where he remained.  About ten o'clock they returned with the Italian peasants from the farm buildings, in all some twelve men and twelve women and children.


Five minutes later Major Pritchard came up, followed by 2nd Lt. A. Paterson, R.E.  Deane-Drummond reported what he had done and Pritchard gave out his orders: Paterson, in the absence of Captain Daly, to examine the aqueduct and decide how to carry out the demolition; the sappers to collect the explosives; the Italians all to be taken down and placed under guard in the farm buildings across the Tragino; the protective parties to be disposed in a semi-circle to the north and down-stream of the aqueduct, under Deane-Drummond, Lt. A. Jowett, H.L.I., and Captain C.A. Lea, L.F.; everyone to assemble at the farther end of the Ginestra aqueduct when the job was done.  The parties were posted; Deane-Drummond on the track by the farm buildings where the Italians were under guard; Jowett downstream where the Ginestra flowed into the Tragino; Lea's party divided, some at the eastern end of the Tragino aqueduct, the remainder at the farther end of the aqueduct over the Ginestra.  Deane-Drummond found that the track was carried over the Ginestra on a rough bridge of rails and concrete, wide enough to take a lorry, which had been built to carry up the material for the construction of the aqueduct and could be used again for repair work.


Paterson made his survey of the aqueduct.  He found it much as he had been led to expect from his study of the description and of the photographs and diagrams, with the important exception of the centre pier.  This was in the middle of the stream and 30 feet high, not squat as shown in the diagram.  He broke the surface of the farther pier with a cold chisel and found it to be of reinforced concrete, as he had feared from the photograph, and not of masonry as in the description.  He was short of explosives, it was out of the question to attack the centre pier or the conduit itself, and he decided to concentrate on the farther pier.  (i - Fur further details of the aqueduct and 2nd Lt. Paterson's appreciation and action, see Appendix I.)


The charges were laid as the explosives were brought up.  When it came to collecting the explosives dropped from his aeroplane three quarters of a mile away, Pritchard decided that the Italian men should be used as a carrying party in order to free the sappers for their skilled work of preparing the demolition.  The interpreters put the matter to them.  Yielding to the show of force, the Italians agreed and worked with a will, saying that it would give them something to talk about for the rest of their lives in a part of Italy where very little happened.  One farmer pleaded that the Tragino aqueduct alone should be blown up, as the destruction of the one over the Ginestra would flood his farm.  He was reassured.


By midnight enough explosives had been carried and Pritchard sent a runner to Deane-Drummond, who was on watch on the track to stop the carrying parties.  Deane-Drummond, finding himself with spare explosives, decided to blow the little bridge over the Ginestra in order to impede the repair of the aqueduct but chiefly, he admits, for the fun of the thing, and sent a message back by runner to Pritchard telling him what he was doing.  Lance-Corporal Watson, R.E., tucked the boxes of explosives comfortably under the rails at the abutment and in a few minutes had the little bridge ready for blowing.


At 12.15 a.m. the main charges on the aqueduct were all in place and the sappers withdrew to the farther end of the Ginestra aqueduct.  The Italian men were taken back to the farm buildings, where two or three were trussed up to encourage the others, warned by the interpreter that the sentry outside the door would shoot to kill, and locked in with the women and children.  No sentry was posted.


A twenty-nine minutes past midnight Paterson fired a one pound guncotton slab, the warning signal that the main charge was to blown a minute later and that the protective parties were to join the sappers.  Paterson and Pritchard lit the fuses and ran for cover over the brow of the hill towards the Ginestra.  On hearing the warning signal Deane-Drummond fired his charge, and he and Watson made for cover fifty yards off.


At half past twelve the aqueduct blew up and half a minute later the small bridge.


The second demolition surprised all but Deane-Drummond's party, since only Pritchard knew of it and had not had time to pass the news round.  Large lumps of concrete and rail from the little bridge fell round Deane-Drummond and Watson who had not got far enough away, and rained down on the roof of the building where the women and children were shut in, though frightened, none were hurt.  Deane-Drummond confesses that he had forgotten all about them when he decided to blow the bridge.


Pritchard and Paterson ran up and examined the destruction of the aqueduct.  The pier had collapsed.  The water way had broken in two where it had been supported.  The two halves were sloping up to the abutment and the centre pier, with the broken ends in the bed of the torrent.  Water was flooding down the ravine.


Operation COLOSSUS was a success.


Pritchard and Paterson then rejoined the sappers and protective parties at the end of the Ginestra aqueduct to find that Deane-Drummond and Watson had just arrived.  For the journey to the coast Pritchard now split up the men into three parties; one under himself with Deane-Drummond, the second under Lea and Paterson, and the third under Jowett and Flight Lieutenant Lucky who had come as one of the interpreters.  The place and date of the rendezvous with the submarine the mouth of the River Sele, fifty miles away, on the night of the 15th/16th February was now told to the sergeants.  This had at first been known to Pritchard and Deane-Drummond alone and had only been communicated to the other officers on the aerodrome at Malta.  The junior ranks were never told.  (1 - See Appendix II).


The heavier arms were thrown away and each party only kept one Tommy gun and their revolvers.  Every man had rations for a week but the parties were divided into groups of three, one man carrying the waterbottles, which they had no difficulty in filling, one the petrol cookers and the third the petrol.  At 12.45 a.m. the parties set off on the journey.


Pritchard led his party up the mountain until they struck the snow.  They kept below the snow line and followed the folds of the mountainside.  At dawn they dropped down to a wood where they lay up for the day.  They were just outside the village of San Lorenzo and only three and a half miles as the crow flies from the aqueduct, although they must have walked at least six.


They set out again after dark on 11th February, and went westwards across country until they struck the Calitri road.  This they followed keeping to the fields until they reached San Andrea di Conza.  They skirted the town to the south and reached the road at the bridge over the Arso.  They crossed by the bridge and kept to the road for the next four miles to the cross roads and for two miles beyond.  Here they left the road and set their course south-west along the flank of the mountain.  Unbeknown to themselves, they were now roughly following the line of the tunnel which takes the water from the sources of the river Sele through the Apennines.  It was now time to look for a hiding place for the day.  Their map showed a wood on the mountain above them.  They climbed higher and higher and struck the snow line to find no woods.  When dawn broke they found themselves on the bare slopes of the Cresta di Gallo.  They scrambled up into the snow and hid in a small cave and behind rocks.


Their tracks in the mud and snow led up to their hiding-place.  It was not long before a farmer came up and found them, and gave the alarm.  Then, from high up the mountains, they watched the search parties approach in the growing light.  First came the village dogs, led by three pointers; then the village children, wondering where the dogs were going; then the women, racing after the children to bring them back, followed by the men going to protect their women folk.  Behind these they saw the organised parties, which had taken longer to get going, arms troops and police slowly advancing in a semi-circle round them.  With their revolvers and tommy-guns they could not have put up a fight, and any attempt at resistance would have ended in hurting the dogs, women and children.


Major Pritchard capitulated.


They were led down to Teoro and put in the lock up at the police station until a lorry arrived.  They went by road to Calitri railway station, where they found Lea's and Jowett's parties who had also been captured that morning.  In the afternoon they were all taken by train to Naples.  After interrogation at Naples, they were sent to a prisoners of war camp.  Here they were joined by Captain Daly and his subsection who had evaded capture for four nights.  Thus the whole thirty-six were captured two nights before the date of the rendezvous with the submarine which would have had a useless journey.


The submarine however had been countermanded.  One of the aircraft which had gone out on a diversionary raid over Calabria as part of the operation had engine trouble over the sea between Sicily and Italy.  The pilot ordered his crew to bale out, but before he crash-landed his aircraft sent out a message in a simple code that he would make for the mouth of the Sele, in the hope that he could be picked up.  The First Sea Lord, being of the opinion that this message had compromised the arrangements for taking off the COLOSSUS parties decided not to risk the submarine and made a signal ordering it not to make the rendezvous.  (1 - See Appendix II).


The precise effect of operation COLOSSUS is difficult to determine.  From gossip with the guards in the camp, Deane-Drummond gathered that the Italians for a short time had great anxiety about the railway bridge over the Tragino.  The sudden flow of water, though it did not apparently rise to the level of the track, might well have scoured out the abutments and made the bridge dangerous.  There is no doubt of the effect on morale.  The sudden and unexpected descent of parachute troops who had succeeded in blowing up an important aqueduct caused widespread alarm.  An organisation akin to the Home Guard was formed to watch important points and air raid precautions were improved.  One may suppose that, in particular, the blackout at Calitri was tightened up.  The destroyed aqueduct was, they had heard, replaced by a syphon within a month, but of interruption to the water supply they had but vague rumours.  Other sources reported that Bari was without water for a few days.


Operation COLOSSUS had a negligible effect on the war in Albania.  It did not achieve a serious interruption to the water supply of Taranto, Brindisi and Bari since the water in the local reservoirs lasted for nearly the whole of the period of repair.  It did however spread great alarm in Southern Italy and caused a large amount of serious effort to be wasted on more stringent air raid precautions and on unnecessary guards.  This was a lasting effect.




Note on the Acquedotto Pugliese and the demolition of the Tragino aqueduct.


The Acquedotto Pugliese is described in the following:-

        (1) Engineering:  an article in Vol. CXXVI No.3267.  August 24th 1928.  London.

        (2) Giornale del Genio Civile.  Anno LVIII 31 Marzo 1920.  Milan.  L'Acquedotto della Puglie.  Prof. Luigi Luiggi and Ing. Raffaele Tramonte.

        (3) Legge, Regolamento e Capitolato per le construzione e l'esercise dell acquedotto pugliese.  1903.  Rome.

        (4) Encylopedia Italiana di scienza, lettere ed arti.  Insituto Giovanni Treccani.  1929.  Milan and Rome.  Article: Acquedotto.


The article in Engineering gives the early history of the project and a technical account of the construction and working of the acquedotto pugliese.  All the details and illustrations are taken from the article in the Italian journal (No.2).  No.3 describes one of the proposed schemes which in the end was closely followed for the part of the system which included the crossing of the Tragino.  The article in the Italian Encylopedia is a good short description with an excellent map of the whole system.


(1), (2) and (3) are available in the Institution of Civil Engineers and (4) in the National Library of Wales.


The project of supplying the arid province of Apulia from the sources of the River Sele which flows into the Mediterranean forty-five miles below Naples, was first put forward in 1868.  The essential feature of the project was a tunnel to carry the water through the Apennines from the western to the eastern watershed, but it was not until the Simplon was built that sufficient engineering experience was available for the construction of a tunnel of such length.  The main system was opened in 1915 and most of the subsidiary branches completed by 1929.  In that year 16,000 million litres of water were sold to consumers (No.4).


The water is collected at Caposele and goes under the Apennines through the Grande Galleria, a tunnel 15 kilometres long.  It is then conveyed by a pipe line down the valley of the river Ofanto.  The larger stream are crossed by arched aqueducts or syphons, the smaller, such as the Tragino, by reinforced concrete aqueducts.  At Venosa, nearly 60 kilometres from the source, is the first important branch, that to Foggia.  The main trunk runs on to Taranto with branches serving the Adriatic coast between Barletta, Bari and Brindisi: 30 kilometres short of Taranto a network of branches south-east to serve Lecce and the heel of Italy.  Service reservoirs are provided for towns and districts to give a three days normal supply in case of interruption.  That for Bari has a capacity of 12 million litres, that for Taranto 12 million.  (No.2).


Clearly the most effective attack on the pipe line could be delivered between Caposele and Venosa as this would interrupt all the distribution systems.  Two targets were considered, the small aqueduct over the Tragino, near Calitri, and the arched aqueduct over the river Bradano, 16 kilometres further down.  Both these are described with photographs in (1) and (2).  The piers of the Bradano aqueduct are massive and its demolition would have required a very great deal of explosive.  The other was selected.


The photograph gives a good general view of the Tragino aqueduct, taken when the buildings erected for its construction were being pulled down.  The diagrams give the dimensions.  The water channel is fixed on the centre pier, slides on to the other two, and rolls on cast-steel rollers on the abutments.  Expanding joints connect each end to the pipe line.  The piers are described as being of masonry ("muratura" - No.2).  In the photograph they have the appearance of reinforced concrete with a masonry base.  The diagram of the aqueduct leaves the impression that the centre pier is not much taller than the other two, but it will be seen that only the part above the base is dimensioned.


The Tragino aqueduct is described as being typical of the small reinforced concrete aqueducts and no mention is made of that over the Ginestra two hundred yards away.  A study of the map, and the profile of the pipe line (in No.3) shows that it was there.


The planners were in doubt about the piers and calculated the charges for masonry for the demolition of all three piers.  If the piers proved to be of reinforced concrete for which six times the amount of explosive would be required, the water way itself was to be attacked.


When he landed, Deane-Drummond was surprised to find the centre pier as high as it was, a surprise which was shared by the others.


Owing to Captain Daly failing to arrive, the responsibility for a successful demolition fell on 2/Lt. Paterson.  In addition to unexpectedly finding himself in charge, he was faced with the centre pier inaccessible, the piers made of reinforced concrete as revealed by his chisel, and only half the explosives dropped.


The explosive situation was not quite as bad as seemed at first sight.  A factor of safety of 100% had been added to the calculated charges and then 50% again added to allow for other contingences.  He had with him therefore 50% above the charge calculated for three masonry piers.


To attack the centre pier at the base alone was out of the question.  He soon found that he could not tamp the charges for a demolition of the water way, the planned alternative if the piers proved to be of reinforced concrete.  He decided to concentrate on the western pier, which was most easily reached.


A charge was laid against the base at ground level on the uphill side and tamped with earth and stones.  Two necklace charges were placed on the upper part, one at the top under the water way and one on the ledge at the top of the base.  With these there was a fresh difficulty.  The two wide surfaces of the upper part of the pier were concave.  Mud had to be pressed in behind the guncotton slabs to make good contact and this slowed up the work.


Paterson deserves the highest praise for shouldering his responsibility, for coming quickly to a decision and for carrying out a masterly demolition.




Note on Security


Lt. Deane-Drummond was flown out to Malta in a Sunderland ahead of the party to make the preliminary arrangements.  He was put in touch with the commander of the submarine and his visits could not have passed unobserved.  Besides him, of the party only Major Pritchard knew of the date and place of the rendezvous, the night of the 15th/16th February at the mouth of the river Sele.  This information was only communicated to the other officers on the aerodrome before the aircraft took off, and to the sergeants after the operation was over.  In Malta, it was known only to the commander of the submarine and certain of the naval staff.  It was certainly not known to the pilots of the aircraft detailed for the diversionary raid, whatever deductions they may have made.


When between Sicily and Italy, one of the pilots, engaged in the diversionary raid, had engine trouble and realised he would have to make a forced landing.  He sent a message in Syko code saying he was 'out of action' and would stay on the coast near the mouth of the Sele for five days.  Deane-Drummond saw the pilot in the prisoners of war camp.  The pilot told him that he had selected the place quickly from his map as one where he could lie up with a chance of being taken off by one of the submarines which he knew operated from time to time near that coast; and that he thought five days a reasonable time to allow before he gave himself up.  He seems independently to have made a quick appreciation resulting in the same answer as to time and place as had been reached in the plan for COLOSSUS.

As the code which he used was simple, it was rightly assumed that the submarine would be jeopardised if it kept the appointment.  The whole of the expedition had been rounded up by the night of the 14th February and the submarine was in fact providentially saved a useless journey.