How Long Must I Work Before I Can Complain Of Unfair Dismissall?
Before you can complain to an Employment Tribunal that you have been unfairly dismissal, the same employer must have continuously employed you for at least one continuous year.

Special rules govern what is "continuous employment". Service is counted in weeks. Statutory maternity leave is included, as are other periods of absence due to pregnancy or child-birth. Periods of absence due to illness or injury, or due to lay-off, are included. If you finish one job and are re-employed by the same employer the following week, you preserve continuity.

Sometimes you can include periods of employment with another employer, e.g. if you move from a parent company to a subsidiary (or vice versa) without interruption; or there is a transfer of an undertaking, or a change in the members of the partnership which employees you. [You may need specialist advice to work out your period of continuous employment.

You do not need one year's service at all if you were dismissed because:

• you were a union member or joined in your union's activities
• you "asserted a statutory right", e.g. complained that you had not be given a pay slip, or of an unlawful deduction from pay, or not getting the national minimum wage
• your dismissal related to health and safety, e.g. you were dismissed for your work as a safety representative, or because you took appropriate steps to protect yourself and others from a serious and imminent danger
• you were pregnant, or for a reason related to pregnancy/maternity, parental leave or dependant leave care
• of your work as a pension scheme trustee
• of your being or seeking election as an employee representative for consultation with your employer on redundancies or transfers of undertakings
• you refused to sign an opt out from the 48 hour maximum working week, or made a claim under the Working Time Regulations
• you "blew the whistle" on malpractice by making a qualifying disclosure to a responsible person under the (complex) Public Interest (Disclosure) Act
• you are a shop worker or betting worker who refused Sunday work
• you supported a union's application to the Central Arbitration Committee for recognition
• you asked to be accompanied to a disciplinary or grievance hearing, or accompanied a worker to a hearing
• you took "protected" i.e. official industrial action
• you claimed adoption, parental, or paternity rights, or requested flexible working
• you claimed the right to equal treatment as a part-time employee with a full-time employee
• you claimed the right to equal treatment as a fixed-term employee with a permanent employee
• you claimed working families' tax credit or disabled persons tax credit
  

If you are dismissed because of your race, gender, disability, religion/belief, or sexual orientation, you can bring a discrimination complaint to an Employment Tribunal regardless of your length of continuous service.