It depends on whether the strike was a form of 'protected industrial action'. Although a strike, or other form of industrial action, is a breach of the contract of employment, which would normally give the employer the right to dismiss, the dismissal would be unfair if the action was 'protected'.
Industrial action is protected if it has been called lawfully, meaning there has been a ballot that complied with statutory procedures, notice was given to the employer, and so on; and where the strike is about a work dispute with your own employer. Workers who take 'unofficial' industrial action or engage in 'wildcat' strikes are not protected from dismissal.
Check with your union if you are concerned about the legality of your planned industrial action.
Dismissal when taking part in protected industrial action is unfair if:
If employees are locked out (prevented from returning to work) during the 12-week period, it will be extended by one day for every day that the employee was locked out.
If you are in this position, take legal advice from a union rep as soon as possible. Deadlines for employment tribunals are extremely short.
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