Restitution in public and private law

accept Air Canada allowed award benefits conferred burden Cannon change of position cited claim based common law concluded contract price Court of Appeal damages defence of change defence of passing defendant Dillon LJ duress efficient breach English Law Commission entitled equitable expense failed failure of consideration fiduciary Goff and Jones Guinness held High Court House of Lords ineffective contract innocent party intervened invalid statute jurisdictions Kerr LJ Law of Restitution liability Lord Goff loss suffered Mancini A. G. ment mistake of law money claims money paid Nambyar paid under mistake party in breach payment plaintiff principle profits public authority quantum meruit question Ralph Gibson reason recover recovery refund remuneration restitutionary claim Rover International salvors services rendered stranger Supreme Court taxes paid taxpayer third party tion tort tortfeasor total failure trust ultra vires unjust enrichment valid West Berkshire wrongdoer