A solicitor from Thompsons' Employment Rights Unit in Belfast, looks at the general principles relating to variation of contract and answers some commonly asked questions.

The law

Although there is no legal requirement on employers to provide a written contract, they do have to provide a written statement of particulars of employment.

This should outline the main terms and conditions including: 

  • the names of the employer and employee 
  • the date employment began 
  • the job title and duties of the job 
  • the place of work 
  • the rate and frequency of pay, hours, holidays, sickness pay and pension scheme/s 
  • notice details 
  • reference to any incorporated collective agreements 
  • details of any disciplinary and grievance procedures

Both parties are bound by the contract and generally neither can vary it without the agreement of the other person.

Frequently asked questions

Can the employer change the contract unilaterally? - If an employer tries to impose a variation of contract, they will potentially be in breach of contract. To decide whether they are, two initial questions have to be asked: 

  • Is the term being varied a term of the contract? 
  • If so, does the employer have the right to unilaterally vary it?

What is a non-contractual term? - A non-contractual term is one that does not legally bind the two parties to the contract.

For instance, it may be very clear that certain allowances are at the discretion of the employer and as such would be deemed non-contractual. As a result, If the employer unilater-ally removes them, this would not be in breach of contract.

It is not always easy to know, however, whether or not the written contract and any other evidence show an intention to be legally bound. Tribunals and courts are often reluctant to rule that a term is non-contractual. To cover themselves, some employers incorporate a specific statement in the contract stating that entitlement to the benefit is non-contractual.

In Albion Automotive v Walker & Ors 2002, the Court of Appeal upheld a tribunal's finding that an established custom of enhanced redundan-cy payments was sufficient to indicate an intention by the employer to be contractually bound to such payments.

Can the employer incorporate a term to unilaterally vary the contract? - A term of a contract may be changed if the contract specifically says so. However the courts will not always enforce such a term.

In the case of Wandsworth London Borough Council v D'Silva 1998, the court said that employers need to use clear language in a contract to be able to unilaterally vary it. This case also suggested that the courts may not uphold such a term where the result would be harsh and unreasonable.

In United Bank Ltd v Akhtar 1989, the court upheld a claim of constructive dismissal despite the existence of an express mobility clause in Mr Akhtar's contract. This was because he was being asked to move city in six days with no consideration for his personal circumstances.

What about changes that are not authorised by the contract? - Where a variation is not authorised by the contract, the employer can still bring it about in one of the following ways: 

  • express agreement between the parties 
  • implied agreement through the conduct of employee 
  • union agreement which is binding on the employee 
  • termination of the existing contract and re-employment under a new contract 
  • What is meant by express agreement?

It just means that there was a clear agreement between the employer and employee, which was voluntary.

If the employee can show that he or she was put under 'duress', they cannot be said to have agreed voluntarily. However, it is not duress if an employer threatens to dismiss the employee if they do not sign.

What is meant by implied agreement? - This will usually arise if the employer purports to unilaterally vary the contract by imposing new terms and conditions and the employee is seen to accept this by their behaviour e.g. by working under the new terms for a long period without protest.

However, the courts are generally reluctant to find that employees have consented to a variation of contract in the absence of an express agreement. 
This is particularly so in cases where the changes do not happen with immediate effect (e.g. changes to sick pay).

What about collective agreements? - As long as a collective agreement is incorporated into individual contracts, employees will be bound by any change negotiated as a result. Employees need not be a union member or even be aware of the collective agreement to be bound by it.

Incorporated Terms

Incorporation of terms may be: express i.e. the individual contract expressly states that terms are governed by a collective agreement. 
Incorporation may also be implied where there is a well-established custom that terms of collective agreements are incorporated into individual contracts. 
When terms of a collective agreement are incorporated into individual contracts, they are legally enforceable.


Can the employer terminate the contract? - If an employer wants to change a term and cannot get agreement for it, they will sometimes terminate the existing contract and offer a new one with the variation.

If the employee is dismissed for refusing to accept the new contract, this will not always be unfair. It will depend on all the circumstances.

If the employer can show a good business reason for the changes, they are likely to be able to establish that the dismissal was for 'some other substantial reason' and was therefore potentially fair.

However, a tribunal will also consider whether the employer behaved reasonably in bringing in the new contract eg by consulting with the employees and unions. A dismissal is more likely to be unfair if the employer just imposes the change without consultation.

What can the employee do? - If the employer imposes a new term or dismisses the employee for refusing to accept the change, an employee may respond in the following ways: 

  • stay and work 'under protest' and bring a claim for unlawful deductions or breach of contract 
  • in the case of a fundamental breach of contract, resign and claim constructive dismissal 
  • if the employer has introduced a new contract which fundamentally changes the job, the employee can continue to work under the new contract and claim unfair dismissal in relation to the old one (Hogg v Dover College 1990) 
  • refuse to work the new terms if, for instance, they involve different duties or hours Ð this may result in dismissal which may or may not be unfair depending on the circumstances.

What can trade unions do? - Unions need to be careful about telling members to refuse to work the new terms. This may be deemed industrial action and, without a ballot, they run the risk that it may be unlawful.

If an employer dismisses more than 20 employees to impose new contracts, they have to consult with the recognised trade union. If they don't, the union can claim for protective awards of up to thirteen weeks' pay.