'Bonaparte' was a British series of naval undertakings between ports on the south-western coast of England and St Brieuc on the the northern coast of Brittany in the northern part of German-occupied France by the motor gun boats of the 15^th Motor Gun Boat Flotilla (18^th January/24 March 1944).

The best known of these five undertakings was 'Bonaparte III' undertaken by Lieutenant P. Williams’s MGB-502, in this instance to land stores and collect agents, escapers and evaders delivered by the 'Shelburn' line. The undertaking was successful, for although the motor gun boat was engaged by a German battery near St Brieuc and had to withdraw, she returned later and despite the ebb tide, which compelled movement across 330 yards (300 m) of bare beach, landed the stores and collected 25 escapers and evaders in four 'surfboats'.

The 'Shelburn' line operated from the Brittany coast in conjunction with the 15^th Motor Gun Boat Flotilla, which had been established in 1942 and operated primarily from from Dartmouth but on occasion Falmouth. Motor gun boats, motor torpedo boats and other light craft such as fishing boats had been operating from this area for crossing to and from north-western France since the defeat of France in June 1940, most sailing from the Helford river and the Scilly Isles until 1942, when the new 15^th Motor Gun Boat Flotilla was based on the Dart river. The flotilla operated this cross-Channel 'service' until November 1944, the unit’s craft operated in the dark period of the month, used grass anchor ropes so that these could be severed with an axe in an emergency. These ropes were also quieter than chains, and with quietness at a premium for operations of this clandestine nature, the oars of the 'surfboats' were also muffled.

The north and west coasts of the Brittany peninsula were used by the Special Operations Executive and the Secret Intelligence Service doe the delivery and extraction of their agents, and it was here that Allied escapers and evaders also gathered to be ferried back to the UK.

The 'Shelburn' line had been created mainly for use in MI.9 rescue operations, and lasted between December 1943 to a final pick-up on the 23/24 July 1944. The 'Shelburn' line was based on the earlier 'Oaktree' line, which was compromised in 1943: many of its current stream of evaders was passed to the 'Burgundy' line. The creation of the 'Shelburn' line resulted from the persistent demands of a French Canadian man, Raymond Labrosse, who had been the 'Oaktree' line’s radio operator. When the 'Oaktree' line was compromised, Labrosse joined a group of evaders, and took them south over the Pyrenees mountains and through neutral Spain to Gibraltar. On return to England he urged on MI.9 that sea evacuations from Brittany should not be abandoned, but undertaken in a different manner.

On 11 October 1942 several evaders gathered in Canet Plage near Perpignan to await collection by a fishing boat from Gibraltar in an undertaking arranged by the 'Pat' line, and among these evaders was a Canadian, Sergeant Major Lucien Dumais of the Fusiliers Mont-Royal. Dumais was a commando who had been captured in the 'Jubilee' raid on Dieppe, escaped and made his way to Marseille on the French Mediterranean coast. Dumais was evacuated by the Polish-manned felucca Seawolf in 'Rosalind' and returned to the UK. Here Dumais volunteered to work with the MI.9 escaper and evader service, but was rejected. After service in North Africa, Dumais again applied for Special Duties, and was accepted.

On the night of 16/17 November 1943, two Westland Lysander aircraft of No. 161 Squadron flew Dumais and Labrosse into a field to the west-north-west of Soissons. The Lysander aircraft returned to England carrying Edgard Potier of the 'Possum' line and five aircrew evaders. The task of the two newly landed men was to establish the 'Shelburn' line, and by December 1943 Dumais and Labrosse had established safe houses in Brittany and a main holding area and safe houses in Paris. Couriers had been recruited locally, a beach selected at Anse Cochat, and MI.9 informed that the line was ready for its first operation. The beach had been codenamed 'Bonaparte'.

Skill of a very high order was needed by navigators on the cross-Channel clandestine service to Brittany, for the coast is difficult and dangerous, with strong currents, vast numbers of hidden rock outcroppings, and very changeable weather. Fog and snow are frequent in winter, and the rapid rise and fall of the considerable tide further complicate the problems of coastal navigation.

The operational plan was for all evaders to be gathered at the line’s holding centres (safe houses) in Paris until a pick-up was imminent. They would then be moved to other safe houses in the coastal region around Plouha and Guingamp for collection once the agreed code phrase had been transmitted by the BBC. The success of the line’s first operation showed MI.9 in London that the 'Shelburn' line was well organised, well prepared and well planned, and had good security.

Most escape line couriers travelled generally with just one or two evaders, but the 'Shelburn' line had, at times, as many as 20 evaders in the back of a truck with shovels and picks: they were instructed to remember a sentence in Polish, and were informed that their cover story was that they were a party of labourers working on the German coastal defences for the Germans.

Evaders were generally given sandwiches and fruit for their journey, and then taken from their safe houses to the coastal cliffs, where they lay 'doggo' as the courier checked the route and the beach for mines which, if detected, were marked with white handkerchiefs. As the 'surfboats' from the motor gun boat neared the beach, the courier signalled the evaders to descend along the cliff path and avoid any white handkerchiefs. With the evader party safely boarded, the courier returned collecting the handkerchiefs as he passed them.

The first operation from 'Bonaparte' beach was 'Bonaparte I' on the night of 28/29 January 1944, when 19 evaders were collected by MGB-503. Taking place on 26/27 February, 'Bonaparte II' against used MGB-503 and collected 18 evaders. There followed 'Bonaparte III' mentioned above, and then 'Bonaparte IV' when, on the night of 19/20 March MGB-503 collected 26 evaders. On the night of 23/24 March some 21 evaders were collected by MGB-503 in 'Bonaparte V'.

'Bonaparte' beach operations were then suspended until a time after the launch of 'Overlord', but then resumed in a series of 'Crozier' undertakings. The first of the series tok place on the night of 12/13 July when 18 evaders were collected by MGB-503 in 'Crozier I'. On the night of 23/24 July six evaders were collected by MGB-502 in 'Crozier II'. The last of the series differed from its predecessors in being a daylight undertaking, and this 'Crozier III' of 9 August used MTB-718 to recover three agents.

In total, the 'Shelburn' line operated from January to August 1944, a period in which eight collections were made to evacuate 136 evaders to England: 94 of these were US airmen, but others were British and Canadian airmen, SAS teams, French agents, and other civilians. It is also worth noting that, in the time before the 'Shelburn' line became operational, comparable undertakings took place, under the aegis of the Special Operations Executive and Secret Intelligence Service, to deliver and collect agents, and whenever possible to evacuate evaders. The Special Operations Executive and Secret Intelligence Service also effected services to and from other beaches between March and July 1944.