Specialist bombing teams (such as 617 squadron) had very high levels of accuracy, but they used the SABS bombsight. During one raid (once they were used to the sight) they dropped bombs on flares laid by the Pathfinder squadron. All their bombs were within 500 yards of the flares, which were off target by a considerable margin. This lead to the use of a Mosquito and eventually a Mustang as the marker plane.
The accuracy was considered high enough to have a couple of goes at the Tirpitz with 5 ton Tallboys, including 1 direct hit. Of course, Tallboys and Grand Slams (10 tons) were ground penetrators who did not rely on accuracy but on subsurface shockwaves - a near miss was considered better than a direct hit.
Interestingly, the USAF have recently redeveloped a 20 ton ground penetrating gravity bomb based on the Grand Slam. I wonder where they would be useful 
Si