use religion as an excuse or kid/dependant lol
A flexibility clause that is vaguely worded for example: ‘the employer reserves the right to change terms from time to time’, cannot be used to bring in completely unreasonable changes. This is because there’s an ‘implied term of mutual trust and confidence’ in all contracts that requires the employer not to act completely unreasonably.
however you can’t be forceably made to work more hours than is stated in your contract. I work 20 hours a week, they can’t force me to work more than this