▁for ▁Ch allen ger . ▁ ▁Spec ification ▁and ▁design ▁of ▁the ▁A 4 1 ▁Cent ur ion ▁began ▁in ▁ 1 9 4 3 , ▁also ▁initially ▁mount ing ▁the ▁ 1 7 - p ound er . ▁It ▁entered ▁service ▁just ▁as ▁the ▁war ▁came ▁to ▁an ▁end . ▁ ▁Infantry ▁t anks ▁ ▁At ▁the ▁start ▁of ▁the ▁war , ▁the ▁Mat ilda ▁I ▁was ▁the ▁current ▁inf antry ▁tank , ▁while ▁the ▁Mat ilda ▁II ▁was ▁in ▁production ▁based ▁on ▁the ▁A 1 2 ▁specification ▁of ▁ 1 9 3 6 ▁and ▁the ▁A 1 2 E 1 ▁prototype ▁of ▁ 1 9 3 8 . ▁ ▁This ▁entered ▁service ▁early ▁in ▁ 1 9 4 0 . ▁▁ ▁It ▁was ▁replaced ▁with ▁the ▁Valent ine ▁tank , ▁based ▁on ▁Cru iser ▁designs ▁and ▁the ▁Mat ilda ▁I . ▁ ▁This ▁was ▁a ▁private ▁vent ure ▁and ▁did ▁not ▁have ▁a ▁specification ▁number . ▁ ▁Design ▁appro val ▁was ▁granted ▁just ▁as ▁war ▁broke ▁out ▁in ▁ 1 9 3 9 . ▁ ▁It ▁was ▁r ushed ▁into ▁service ▁to ▁replace ▁losses ▁in ▁the ▁D unk irk ▁ev acu ations . ▁ ▁Work ▁on ▁the ▁Church ill ▁inf antry ▁tank ▁had ▁begun ▁before ▁the ▁war ▁began , ▁with ▁specification ▁A 2 0 . ▁ ▁This ▁developed ▁into ▁the ▁A 2 2 ▁specification ▁when ▁France ▁was ▁lost , ▁and ▁front line ▁requirements ▁changed . ▁A 2 2 ▁had ▁rapid ▁development , ▁with ▁design ▁completed ▁around ▁one ▁month ▁after ▁the ▁specification