 In the 20th century several changes took place , with the Ballroom becoming a cinema , until the Society for the Protection of Ancient Buildings became the owners in 1931 . The building was restored by A <unk> Green in 1938 , with Oliver <unk> as the interior designer . During the Bath Blitz of 25 / 26 April 1942 , one of the retaliatory raids on England by the <unk> Blitz following the RAF 's raid on <unk> , the Assembly Rooms were bombed and burnt out inside . After the cessation of hostilities in Europe , they were restored by Sir Albert Richardson , with work being completed in 1963 . The ballroom ceiling had to be repaired after it collapsed in 1989 . 
