From Lawpack's Your Rights at Work.
Generally, your employer cannot change the terms of your contract without first obtaining your agreement. However, there are some changes that your employer can make if it has built 'flexibility' into your contract, for example, by stating that 'You may be required to work anywhere in the UK' or that 'You will work eight hours in 24, day, night or shift work'.
Another way flexibility may have been built into your contract is by the use of terms that can be altered or removed. For example, entitlement to a bonus may be stated to be at your manager's discretion and/or your employer may reserve the right to remove entitlement to a bonus without compensation.
A staff handbook 'as issued from time to time' may be stated to be incorporated into a contract. This would mean that matters dealt with in a handbook could be changed and that change would be automatically incorporated into the contract, without the need of your employee's express consent.
If the contract contains such flexibility, then your employer will be able to alter the terms in line with these clauses provided it introduces the changes in a reasonable manner. For example, if a mobility clause is included in the contract, your employer should give reasonable notice before requiring you to relocate.
If there is no flexibility, then your employer must follow the correct procedure if it wants to alter your terms of employment. Your employer must offer the new terms to you; you can either accept or reject them. If you do nothing, this doesn't mean that you have accepted the new terms. The only time doing nothing can amount to acceptance is when your employer's letter varying the terms says something like, 'If you do not object in writing within 14 days, you will be deemed to have accepted the change'. Alternatively, it's possible for you to accept the new terms by your conduct; if you change your behaviour to comply with a term in the offer (e.g. you turn up for work at a new time), you will be judged to have accepted the new terms. You could also continue to work under the new terms under protest making it clear that you are not accepting the revised terms and are treating the changes as breach of contract.
If you don't accept the changes, your employer may dismiss you and then offer employment on the new terms. However, if this happens, you may have a claim for breach of contract, unfair dismissal or redundancy if the correct procedures are not followed and fair reasons for dismissal don't exist.
Law stated as at 1 March, 2006
