The Type IXC/40 boat U-540 left Bergen on 4 October 1943 for its first war cruise under the command of Kapitanleutnant Lorenz Kasch, but was attacked on 16 October when west of Eire by Liberator G.R. Mk.V (FL984) of No.59 Sqd., flown by Pilot Officer W.J.Thomas from Ballykelly, Northern Ireland. It survived this attack but its ordeal continued the following day. The following day U-540 was attacked by two more Liberators from Reykjavik, Iceland. These were Liberator G.R.Mk.V (BZ712) of No.59 Sqd., flown by Lieutenant Eric Knowles, and Liberator G.R.Mk.1 (AM929) of No.120 Sqd., flown by Warrant Officer Bryan W. Turnbull (RNZAF). Knowles made two attacks and on the second the depth charges were seen to straddle the U-boat. Turnbull also made two attacks, one of which is shown here. The U-boat was destroyed with the loss of all fifty-five crew members. Ref: ADM 199/1415
