An employment contract is required as part of UK law, and is defined on the Government website as requiring employment conditions, employment rights, responsibilities and duties.
This contract defines the employees rights to working conditions, their responsibilities and duties, and of course the pay.
The contract is enforeable in law until it is ended, under it's conditions, by either the employer or employee. This can be by agreement to change the contract, or by ending the agreement by giving notice or by the employee being dismissed. Surprisingly the Government states that "An employment contract doesn’t have to be written down", though employment lasting more than a month must have a written statement of employment particulars.
This statement must include:
- the business name
- employee's name
- job title and description
- pay and time of pay
- hours of work
- holiday entitlement
- location of work
The terms of the contract can be written down in a document, verbal, or even on the company notice board. Other applicable terms are those accepted by trade unions, or implied by the law or common sense. One example is having a valid driving license if you accept a job as a lorry driver. Other examples of implied contract terms are not stealing, being granted the minimum holiday entitlement, health & safety at work, and the minimum wage.
Further information is available at: Employment Contracts on the Government website.