The British Embassy in Tunisia is located in the city of Tunis close the the US Embassy. If you are in Tunisia and in need of assistance then the British embassy can assist you in an emergency or if you need to apply for a passport.
They can also issue a visa for you if you as a Tunisian would wish to visit or live in the United Kingdom. Speak to the embassy staff about what can be issued at the embassy. The contact details of the embassy have been listed below.
British Embassy in Tunis
Rue du Lac Windermere
Les Berges du Lac
Office hours: Mon to Thurs, 8.00am to 4.30pm : Fri 8.00am to 1.00pm (local time)