In order to bring a claim for unfair dismissal, the applicant must:

• be an employee
• have been dismissed
• have been continuously employed for at least one year (unless dismissal related to certain reasons e.g. trade union membership, health and safety or pregnancy)
• not be within an excluded class
• have complied with the resolution procedures, if applicable

• relating to the capability or qualifications of the employee to do work of the kind which he was employed to do
• relating to the conduct of the employee
• that the employee was redundant
• that the employee could not continue to work in the position held without contravening some statutory provision (illegality)
• there was some other substantial reason (SOSR) justifying dismissal of an employee holding the position which that employee held
• retirement.

If the employer establishes a potentially fair reason, the tribunal will then look at if they behaved reasonably.

In cases of misconduct or poor performance, the employer should comply with the Acas Code of Practice on Disciplinary and Grievance Procedures. Failure to do so may lead to a finding of unfair dismissal and the tribunal may increase compensation by up to 25% if the failure was unreasonable. For dismissals on the grounds of retirement, employers are required to implement a "planned retirement" procedure as the employee approaches retirement age. They must give the employee at least 6 months’ written notice of the proposed retirement date, and consider any request by the employee not to retire.

For other types of dismissal, including redundancy, there is still a requirement to follow a fair procedure. It is important to give an employee sufficient information about the reasons for their possible dismissal, and the opportunity to respond at a hearing or meeting, before reaching a final decision. It is also advisable to give a right of appeal in most cases.

The tribunal will have regard to matters known to the employer, the size of the undertaking, whether the reason justifies dismissal, pressure on the employer, any breaches of contract, equitable considerations (e.g. a long-serving employee deserves more consideration before dismissal), consistency, human rights, codes of practice, and procedural defects.