▁sister s ▁asked ▁for ▁the ▁next ▁r ental ▁payment , ▁this ▁had ▁trans p ired ▁and ▁Mr ▁Cooper ▁sought ▁a ▁declaration ▁that ▁he ▁was ▁the ▁owner ▁and ▁that ▁the ▁le ase ▁was ▁not ▁en force able . ▁ ▁Jud gment ▁The ▁House ▁of ▁L ords ▁held ▁that ▁the ▁contract ▁was ▁void able ▁at ▁Mr ▁Cooper ’ s ▁instance , ▁on ▁the ▁basis ▁of ▁a ▁mistake ▁that ▁it ▁was ▁possible ▁for ▁the ▁a unt ▁and ▁sister s ▁to ▁le ase ▁the ▁land ▁to ▁Mr ▁Cooper . ▁Since ▁Mr ▁Cooper ▁was ▁the ▁true ▁benef icial ▁owner , ▁in ▁equ ity , ▁it ▁was ▁impossible ▁for ▁a ▁le ase ▁to ▁be ▁granted ▁to ▁him ▁in ▁law . ▁ ▁Lord ▁C ran worth ▁said ▁the ▁following . ▁ ▁Lord ▁West bury ▁agreed , ▁and ▁expressed ▁the ▁issues ▁as ▁follows : ▁ ▁Lord ▁Col ons ay ▁con cur red . ▁ ▁Sign ific ance ▁The ▁case ▁has ▁been ▁seen ▁as ▁an ▁example ▁of ▁how ▁a ▁contract ▁will ▁be ▁un en force able ▁if ▁there ▁is ▁a ▁mistake ▁by ▁both ▁parties ▁about ▁the ▁possibility , ▁in ▁law , ▁to ▁perform ▁a ▁contract . ▁This ▁doctrine ▁of ▁mistake ▁in ▁equ ity ▁was ▁expanded ▁upon ▁by ▁Den ning ▁L J ▁in ▁Sol le ▁v ▁But cher , ▁which ▁emphas ised ▁that ▁mistakes ▁in ▁equ ity ▁would ▁render ▁a ▁contract ▁void able ▁( at ▁the ▁instance ▁of ▁the ▁claim ant ), ▁rather ▁than ▁void . ▁However , ▁mistake ▁in ▁equ ity ▁was ▁held ▁to ▁have ▁been ▁abol ished ▁in ▁The ▁Great ▁Peace