, ▁as ▁decided ▁in ▁R ▁v ▁North ▁and ▁East ▁Dev on ▁Health ▁Author ity , ▁ex ▁parte ▁C ough lan , ▁was ▁that ▁there ▁must ▁be ▁a ▁" clear ▁and ▁un ambigu ous " ▁promise ▁made ▁that ▁led ▁to ▁a ▁reli ance ▁or ▁a ▁det r iment ; ▁Robin ▁Cook ' s ▁statement ▁after ▁the ▁first ▁B anc ou lt ▁case ▁could ▁not ▁be ▁described ▁as ▁a ▁clear ▁and ▁un ambigu ous ▁promise ▁of ▁res ett lement , ▁and ▁the ▁requirements ▁of ▁reli ance ▁and ▁det r iment ▁were ▁not ▁met . ▁ ▁L ords ▁B ingham ▁and ▁M ance , ▁diss ent ing , ▁took ▁the ▁view ▁that ▁the ▁Order ▁in ▁Council ▁was ▁un reason able ▁and ▁therefore ▁invalid . ▁B ingham ▁noted ▁that ▁the ▁proper ▁way ▁to ▁interpret ▁an ▁exercise ▁of ▁the ▁royal ▁pr er og ative ▁was ▁to ▁look ▁at ▁how ▁it ▁had ▁been ▁exerc ised ▁previously , ▁and ▁that ▁he ▁could ▁not ▁find ▁any ▁previous ▁record ▁of ▁the ▁pr er og ative ▁being ▁used ▁to ▁" ex ile ▁an ▁ind igen ous ▁population ▁from ▁its ▁hom eland ". ▁ ▁He ▁argued ▁that ▁this ▁pr er og ative ▁power ▁did ▁not ▁exist : ▁"[ t ] he ▁Crown ▁has ▁never ▁had ▁a ▁pr er og ative ▁power ▁to ▁prevent ▁its ▁subjects ▁from ▁entering ▁the ▁Kingdom , ▁or ▁to ▁exp el ▁them ▁from ▁it ". ▁According ly , ▁the ▁Order ▁was ▁ult ra ▁v ires . ▁B ingham ▁also ▁maintained ▁that ▁it ▁was ▁ir r ational , ▁since ▁vis its ▁to