The order had been "idiotic and disgraceful", said Sir Paddy, who was a Royal Marine captain before he was leader of the Liberal Democrats. His father, who ended the war a colonel, was in the Royal Indian Army Service Corps, based in the Punjab. In 1939 he took a platoon of Indian soldiers and their troop of mules as one of four mule trains to join the British Expeditionary Force in France.

During the BEF's 100-mile retreat in June 1940, the order went out from a senior British officer to set loose the mules and the Indians; the British officers were ordered to make their way to Dunkirk for evacuation, since officers were in short supply.

Sir Paddy's father, John, disobeyed, turning loose the mules but marching his platoon to Dunkirk without loss. There he secured a berth for them all on the last ship out before the jetty was bombed. Back in England, he was reunited with his wife, Lois, but court martialled for disobeying an order. The court martial was subsequently thrown out, according to Sir Paddy.

The Ministry of Defence, when first approached about the story by the Southall-based TV company Zee TV, said its archive department had after two days been unable to find any record of Indian troops at Dunkirk; it also reported it had lost the records of Indian Army court martials. Zee TV located a record of the Indian troops' presence in hours at the Imperial War Museum. The ministry then asserted that the command to cut loose the Indians and mules, made by a single officer, did not amount to an official order.

Sir Paddy said last night: "It may seem that the order was a racist one in the context of our time, but my father thought simply that these were his men, he was responsible for them, and he must bring them back. That was the beginning and the end of it."