
@ Optymystic
"No, it is not so and obviously. A policy is not a contract, changing a policy is not a justification for voiding a contract;"
Absolutely. Though it could be motivation for finding grounds to do so.
"... passing a law to make a contract illegal is likely itself to be contrary to law and before you ask, yes, there are hierarchies of laws and rules about what is legal, there are constraints on the powers of parliaments, there are structures for challenge to law makers on, natural law, human rights, constitutionality etc."
Utter drivel. Parliament is supreme. It has several times passed retrospective legislation (notably the Act of 2001 retrospectively legalising arbitrary retention of DNA samples by police), and is not bound by natural law, human rights, or anything but its own malleable procedures. Roughly half of all legislation is interefering in freedom of contract in some way - and that includes ALL of employment law - so your final paragraph is bollocks, too.