The concept of daytime raids quickly ended after the disastrous Air Battle of the Heligoland Bight, in which a force of Wellingtons was cut apart. For the rest of the war, the RAF was convinced night bombing was the only survivable strategy and this opinion was not seriously reconsidered. Both Fighter and Bomber command evolved doctrinal arguments against escorts, even after photoreconnaissance versions of the Spitfire were flying deep into Germany at ranges that would allow them to escort daytime bombing.