'Scipio' (i) was the Allied unrealised original plan for the seizure of Dakar in French West Africa (early July/13 August 1940).
The original 'Scipio' (i) concept had its origins in the first part of July 1940 with Prime Minister Winston Churchill and Général de Brigade Charles André Joseph Marie de Gaulle, the leader of the Free French movement: the former saw the seizure of Dakar the enticing prospect of of a considerable strategic reward for a minimal and risk-free British military investment, and the latter of bringing a significant part of Vichy France’s overseas territories into the Free French fold.
Clearly the most important of these Vichy French possessions were French North Africa, French West Africa (Afrique Occidentale Française) and French Indo-China, where it was hoped a blend of Allied propaganda followed by the arrival of French ground forces would sway the political balance without the need for conflict. Of the three main targets, French West Africa seemed to offer the best chance of success, and the British and French leadership thus considered the landing of a French force of about brigade strength at Dakar in French West Africa, or at Conakry in French Guinea, or at Douala in French Cameroun. However, the political sponsors of the plan failed to take into account the facts that the leadership of the colonies might adhere strongly to the Vichy French cause and that naval support for these regimes might be provided from Vichy France or its possessions in North and West Africa.
Nine days before his expulsion by the Vichy French, the British consul-general in Dakar had suggested to London that many of the local civil and military leaders were so keen to continue the war at the UK’s side that an early appearance by British warships off Dakar would lead to a bloodless coup d'état. This report served to confirm earlier optimistic reports, delivered via the Colonial Office, by British liaison officers still in French West Africa. On 5 July Churchill minuted that the consul-general’s suggestion 'appears to be of the utmost importance'. Major General H. L. Ismay, the chief-of-staff to the minister of defence (i.e. Churchill), responded swiftly with a sober military appreciation of the strength of Dakar’s defences (including the battleship Richelieu), indicating that caution was demanded.
This simple exchange served to establish the pattern of the developments which now ensued: the demands for action as soon as possible by an enthusiastic Churchill, and the exposition of the operational difficulties by the unhappy military, who nonetheless complied with the prime minister’s wishes. Indeed, at the beginning Churchill even bypassed the Chiefs-of-Staff Committee altogether in favour of consultation with an informal clique of advisers in touch with de Gaulle, who together conceived the 'Scipio' (i) initial operational plan, in which Free French forces were to play the active role.
On 8 July, the battleship Richelieu was attacked in Dakar by a force comprising the small carrier Hermes and the heavy cruisers Dorsetshire and Australian Australia under the command of Captain R. F. J. Onslow. In the early morning of the day in question a motor boat penetrated the harbour defences and dropped depth charges under the battleship’s stern, but these failed to detonate. Three hours later Fairey Swordfish torpedo bombers from Hermes obtained one hit which distorted a propeller shaft and flooded three compartments. The damage was severe enough to give the Vichy French a year’s repair work to render the battleship fully seaworthy, although the ship could still have put to sea in an emergency.
On 4 August the Chiefs-of-Staff Committee gave its support to 'Scipio', albeit with considerable reluctance, on the clear understanding that the British role was to be limited to providing equipment and the naval escort.
But now Churchill had the bit fully between his teeth for, with the urging of Admiral Sir Roger Keyes, the Director of Combined Operations, he had already endorsed the 'Workshop' notion of taking the Italian island of Pantelleria and planned the concept which was to mature as the commandos for attacks on Germany’s European coastline, was and within three days it had become accepted that British troops would also be involved. Impatient with the Chiefs-of-Staff Committee’s caution, Churchill instructed its 'Let a plan be prepared forthwith…'. When all the considerations were finally taken into account during August 1940 it was decided that a greater British involvement would be necessary to provide the strength necessary for a coup-de-main against Dakar, now fixed as the target for the initial effort of what had now become a military rather than political operation.
The resulting plan called for an assault landing on Dakar by more than five battalions of Royal Marines, the date was then set for 8 September, and the operation became 'Menace', which the war cabinet approved on 13 August.