Make a manifesto and pre election promises a contract that has to be delivered

Background

Once elected a MP can do as they see appropriate and take action accordingly. This negates any pre election promise or manifesto since a party can promise actions but once elected can completely change their minds. I call on the government to make a manifesto a form of contract that is enforceable

Additional details

The public have lost faith in the people and parties that are running the country and this action I am asking would help restore faith in a system that can be used in appropriately. A party can promise the public the earth yet once elected deliver the exact opposite, parties have access to facts and figures and should only promise that which they know they can deliver. If a party does not deliver that which it said it would do then serious action should be taken even including an election.