Robert Clerk Lieutenant - Colonel Robert Clerk was a British engineer officer who served in the War of the Austrian Succession and the Seven Years ' War . His report on the state of the defences of Rochefort ( Rochefort , Charente - Maritime ) in 1757 was the main reason for that French naval port being chosen as the target for a major British expedition , the Raid on Rochefort , for which Clerk was appointed chief engineer . Early career . Robert Clerk ( sometimes spelled Clark or Clarke ) was born about 1720 , the son of an Edinburgh physician . John Entick speaks of him as a worthy , intelligent , skilful officer . However Horace Walpole wrote , " ” There was a young Scot , by name Clarke , ill - favoured in his person , with a cast in his eyes , of intellects not very sound , but quick , bold , adventurous . ” " Clerk entered the Army as a second lieutenant in Cotterrell ' s Marines with seniority 11 June 1741 . He was appointed a practitioner engineer on 24 May 1749 , promoted to sub - engineer on 30 May 1753 , while also becoming a lieutenant in the 25th Regiment of Foot on 2 Oct 1755 . In 1745 Clerk went as " “ a Volunteer with Sir John Mordaunt to Ostend , but they did not arrive , till after the Siege ; he saw the Attack , and was afterwards in the trenches . ” " In 1746 , Clerk was appointed as an engineer - in - ordinary to an expedition , commanded by General St Clair , to take Quebec . Due to the lateness of the season , in September the force was diverted to Port L ’ Orient in Brittany . In 1747 Clerk was an engineer with the Anglo - Dutch troops defending the town of Bergen - op - Zoom against the besieging French army led by Count Löwendahl . After a long and destructive siege the town was taken by a surprise assault and Clerk captured ; " “ being pursued into a house where the enemies fired at him through a door , he opened it and told them he was related to Marshal Löwendahl , who would reward them for saving him . Being conducted to the Marshal , with the same readiness he avowed the deceit , urging that he had no other method of saving his life . Löwendahl was pleased with the man , and gave him money . ” " Clerk was held as a prisoner of war and not released until the end of the war in 1748 . Background to the Raid on Rochefort . In Clerk ' s own words , " “ In returning from Gibraltar in ( April ) 1754 , I went along Part of the western Coast of France to see the Conditions of some of their Fortifications of their Places of Importance , on purpose to Judge if an Attempt could be made with a Probability of Success . . . I had heard that Rochefort , tho ’ a Place of the utmost Importance , had been very much neglected . I went there , and waited upon the Governor in my Regimentals , told him , that I was upon my Way to England from Gibraltar , and that I came on purpose to see the Place , the Dock , and the Men of War . He was very polite ; I was shewed every Thing , went on board ten Ships of the Line new built , and an Engineer attended me in going round the Place . . . I got no Plan of the Place , and put nothing down in writing , for I found that the whole Town had been talking of me , and thought it very extraordinary , that I should be allowed to go about and see every Thing . ” " At this time Clerk was only a sub - engineer in the corps of engineers ( and therefore a lieutenant from 14 May 1757 when engineers were first given military rank ) , but he is referred to as Captain Clerk in most histories of the time and was also described on the Engineer List as " being with his regiment . " He must therefore have also held a captaincy in the British Army , the engineers at this date not being part of the Army under its commander - in - chief but being ordnance troops under the command of the Master General of the Ordnance . Despite his relatively low rank Clerk mentioned his visit to Rochefort to the commander - in - chief of the British Army , General Ligonier , who asked him to put down his observations in a letter , which Clerk did on 15 July 1757 . By early August 1757 Rochefort had been decided by Pitt as the first target for his planned series of descents on the coast of France . Command of the expedition was given to Lt - Gen Sir John Mordaunt and " Clerk was appointed Chief Engineer , and the unprecedented step was taken of promoting him at a bound to the rank of Lieutenant - Colonel , he being at the time only a Lieutenant ( Commission Book , No . 1270 , p . 266 ) . This is the sole instance on record of such rapid promotion having been given to any Engineer . Under him were Sub - Engineers Richard Dudgeon and Thomas Walker , and Practitioners Robert G . Bruce , Augustus Durnford , William Roy , and John C . Eiser . " The Raid on Rochefort . The expedition left England on 8 September 1757 and on the 23rd the fleet entered Basque Roads , battered the fort on Île - d ' Aix and captured the island . On the 24th Clerk was sent by Mordaunt to Aix to examine prisoners regarding the state of the defences of Rochefort but got no useful answers . After dinner Clerk went in the dark with Captain Howe of the Magnanime and Mr Boyd , the Controller of the Train , to reconnoitre Fouras . They landed at the tip of the promontory at low tide and walked over spongy ground for a couple of miles to within about a mile of the fort . On the 25th a council of war was held and it was determined that an attempt upon Rochefort was neither advisable nor practicable . Clerk again visited the Île d ' Aix to examine prisoners , in particular a French engineer . His idea was to give the impression that he knew everything and to let the prisoners confirm his thoughts during casual conversation . On the 28th another council of war was held and it was resolved to land in Châtelaillon Bay , however , due to the tide and weather the landing that night was abandoned . Despite this , Clerk was further employed the next day in accompanying Maj - Gen Conway and Col Wolfe to carry out further reconnaissance of the proposed landing sites at Châtelaillon . Meanwhile during the day of the 29th the demolition of the Aix fortifications was commenced : " “ The following two days were spent in blowing up the half - finished fortifications on the Island of Aix ; and in doing of which , lest it be said that no blood was spilt upon our famous expedition , we managed so as to blow up a few of our own soldiers . ” " On 1 October 1757 the fleet weighed anchor and on the 6th arrived back in England . Inquiry and Court - Martial . On the return of the fleet with nothing to show for the great expense of the expedition , both Pitt and the King were understandably annoyed . On 1 November the King issued a warrant for an inquiry , Clerk being among the many called as witnesses . On the 21st it reported its findings and the King ordered Mordaunt to be tried by court - martial for disobeying his instructions . The court - martial opened on 14 December 1757 . Wolfe was quite clear in his mind , " “ The whole affair turned upon the impracticability of escalading Rochefort , and the two evidences brought to prove that the ditch was wet ( in opposition to the assertions of the Chief Engineer , who had been in the place ) , are persons to whom , in my mind , very little credit should be given . Without their evidence we should have landed , and must have marched to Rochefort ; and it is my opinion that the place would have surrendered or been taken in forty - eight hours . ” " Clerk was quizzed at some length and , though being always careful to say he could only say what he had seen more than 3 years before , he maintained his assertion that not all of the ditch around the town could be flooded as parts of it were higher than the tide could reach . Subsequent career . Despite having been instrumental in the choice of Rochefort as a target , Clerk seems to have escaped any blame for the failure ; indeed , he was associated with Wolfe as a bold , adventurous young officer held back from capturing Rochefort by the timidity and indecisiveness of superannuated commanders . Clerk continued to mix with the highest levels of society . On 1 December 1757 , while both he and Wolfe were on notice to be witnesses at Mordaunt ’ s court - martial , Wolfe wrote to his mother , " “ ( Tomorrow ) night I am to meet ( the ) guest ( of my old friend Rich ) , who is sent by the King of Prussia ; Mr . Keith , our late envoy at Vienna ; a son of Field - Marshal Count Lacy ' s ; and Colonel Clarke , the engineer . These , with myself , make five very odd characters , and for the oddity of the mixture I mention it to you . ” " Clerk ’ s particular talents were much lauded by some ; Lord Bute said of him , " “ With regard to Clarke , I know him well : he must be joined to a general in whom he has confidence , or not thought of . Never was a man so cut out for bold and hardy enterprises ; but the person who commands him must think in the same way of him , or the affair of Rochfort will return . ” " This was a prescient remark because even as it was written on 8 September 1758 , Clerk ’ s impetuosity was getting him into trouble . In 1758 Clerk , who had resigned from the Corps of Engineers on 1 Jan 1758 , was appointed to the staff for the expedition to Cherbourg in Brittany . After taking and burning Cherbourg the expedition , led by Major - General Edward Bligh , made an ill - advised attempt to take St Malo , but the land forces were abandoned by the navy and had to fight a disastrous rear - guard action at St . Cast . Clerk ’ s conduct in this action led to his arrest : " “ General Blighe … had been actuated , during the course of these enterprises , by a young Lord Fitz - morrice and the adventurer Clarke , who diverted himself from the ships with the difficulties his comrades found in re - embarking . But he was on the point of falling under the punishment due to his arrogance : depending on his interest in the General , he had broken the arrest under which he had been put , for some misdemeanour , by Cunningham , his commanding officer ; the same Cunningham , whose handsome behaviour at Minorca I have mentioned : at his return from thence he had been preferred by the Duke , who told him he had been misinformed of his character , and was sorry he had not sooner known his merit . At their return from St . Cas , Cunningham insisted on bringing Clarke before a Court - Martial . The Princess ( Princess Augusta of Saxe - Gotha , Dowager Princess of Wales ) unwisely countenanced the latter , who had made himself odious to the Army , and who escaped . ” " Even while Clerk was under arrest he continued to exert his charm . On 16 October 1758 " “ Clarke was talked to by the Princess yesterday much more than any body in the room . ” " Despite his court - martial , Clerk progressed through the ranks of the army becoming colonel on 19 February 1762 , major - general on 25 May 1772 , lieutenant - general on 29 October 1777 and general on 12 October 1793 , before dying on 22 May 1797 . Robert Clerk appears to have been an impulsive adventurer , not lacking in charm , confidence or self - promotion . Though from an apparently middle class background , he mixed in the highest circles , rose rapidly in the military and had a modest , if brief , impact on history .