705 aircraft - 476 Lancasters, 207 Halifaxes, 22 Mosquitos. The sudden switch by Bomber Command to a Ruhr target just across the German frontier caught the German fighter controllers by surprise and only 9 aircraft - 6 Lancasters, 3 Halifaxes - were lost.
Essen was covered by cloud but the Oboe Mosquitos marked the target well and this was a successful attack