wellington bomber

how many marques of this aircraft were produced including prototypes and test beds etc please as an aside to this id heard a story concernung the wellington from a chap who worked at the then air ministry of a project to evaluate the possible conversion of the bomber to carry a “nuclear” device this was circa 1944/5,there was a test area off the north coast where the device was to be air drop tested in a smaller form there were some large observation bunkers built on the coast to accomadate the project. it sounds off the wall ,however the gentleman concerned was adamant this project was put up for consideration, barnes wallis was consulted about the wellingtons airframe suitability ,as there were no lancs available and halibags werent even considered, 😎 😎