You are not entitled to be paid for days you did not work. An employer’s failure to pay when workers go on strike is a lawful deduction from wages.
Refusing to work by going on strike puts you in breach of your contract of employment. However, as long as your strike was called in accordance with the laws governing industrial action you are protected from dismissal. This protection lasts for a period of 8 weeks although some voices within the Conservative-led government have called for this protected period to be reduced.
