agen arian ▁composer ▁had ▁settled ▁into ▁ben ign ▁tran qu ill ity ▁was ▁disp elled ▁by ▁his ▁Six th ▁Sym phony ▁( 1 9 4 8 ), ▁described ▁by ▁the ▁critic ▁G w yn ▁Par ry - J ones ▁as ▁" one ▁of ▁the ▁most ▁disturb ing ▁musical ▁statements ▁of ▁the ▁ 2 0 th ▁century ", ▁opening ▁with ▁a ▁" pr imal ▁sc ream , ▁pl ung ing ▁the ▁listener ▁immediately ▁into ▁a ▁world ▁of ▁ag gression ▁and ▁imp ending ▁cha os ." ▁Com ing ▁as ▁it ▁did ▁near ▁the ▁start ▁of ▁the ▁Cold ▁War , ▁many ▁critics ▁thought ▁its ▁pian iss imo ▁last ▁movement ▁a ▁dep iction ▁of ▁a ▁nuclear - sc orch ed ▁was t eland . ▁The ▁composer ▁was ▁dismiss ive ▁of ▁program m atic ▁theories : ▁" It ▁never ▁seems ▁to ▁occur ▁to ▁people ▁that ▁a ▁man ▁might ▁just ▁want ▁to ▁write ▁a ▁piece ▁of ▁music ." ▁ ▁In ▁ 1 9 5 1 ▁Ad eline ▁died , ▁aged ▁eight y . ▁In ▁the ▁same ▁year ▁V aug han ▁Williams ' s ▁last ▁opera , ▁The ▁Pil gr im ' s ▁Progress , ▁was ▁st aged ▁at ▁Cov ent ▁Garden ▁as ▁part ▁of ▁the ▁Festival ▁of ▁Britain . ▁He ▁had ▁been ▁working ▁inter mitt ently ▁on ▁a ▁musical ▁treatment ▁of ▁John ▁Bun yan ' s ▁alleg ory ▁for ▁forty - five ▁years , ▁and ▁the ▁ 1 9 5 1 ▁" mor ality " ▁was ▁the ▁final ▁result . ▁The ▁reviews ▁were ▁respect ful , ▁but ▁the ▁work