Well, personally, I feel the Wellington deserves that honour...they made 47,409 sorties in Bomber Command, including 6,000 odd by OTU's, and dropped nearly 42,000 tons of bombs. In all, the Command lost 1,332 on Ops plus a further 337 in accidents. On Ops from the UK, they flew 63,976 sorties, totalling 346,440 hrs of flying. In the MTO and Far East, flying hours totalled 524,769, and they dropped nearly 100,000 tons of bombs. After the War, they continued to fly as trainers for 350,000 odd hrs...They built a total of about 11,500 of them, first designed in 1936, blooded in combat 4th Sept. 1939, the 2nd day of the War and was still in production on VE Day...It was designed by Barnes Wallis, famous for it's remarkably durable geodetic construction, took a 4,000 lb 'cookie' and was pleasant to fly, altho' slow at 180- 250 mph odd, but with 2,500 miles range and was loved by it's crews...
Apart from that , RAF 75[NZ] Sqn. was the first to have them, and a chap called F/S J.A. Ward from my l'il old hometown won the Victoria Cross after climbing-out on a wing and putting a fire out, in July 1941, heading back from a raid on Munster...I went to the same college, and they had his medal there....