I have received a reference request relating to an ex-employee; do I have to provide one?
The simple answer is no, there is no legal duty to provide this kind of information to another company or potential employer. There are some exceptions which relate predominantly to the finance sector, but generally speaking if these exceptions apply to you, you will already know about them.
Most employers are not obliged to provide a reference about an employee or ex-employee, whether the request for a reference comes from the employee, a prospective employer or any other third party, such as a bank or landlord. Many companies have set policies on giving references which stipulate that they only include basic factual information about the employee's length of service, position held, pay etc.