If changes are made to someone's main terms of employment, the employer must put them in writing. For example, they might send the employee a letter or email.
It's a good idea for the employer to put all contract changes in writing. This helps to make sure everyone is clear about what is changing so there is less chance of misunderstandings or disagreements.
The employer might choose to update the 'written statement of employment particulars' but they do not have to.
By law, the employer must put a change in writing within 1 month of the change.
Changing an employment contract
There are important procedures to follow when changing the terms of an employment contract.