Please can you tell me if I married a tunisian man in tunisia can I divorce in england

Did you apply UK immigrant visa for him? If yes.. you can file the divorce in UK.

Assuming that you are commonly Domiciled in England/Wales then a divorce is petitioned for under jurisdiction of English law.
It is irrelevant whether a Visa was applied for. To file for divorce you must have been married for a minimum of 1 year and then apply a specific reason for wanting to divorce. Contact me for further information.