The shipwrecked Kurdish asylum seekers will be sent back to France if they try to get into Britain.
A Home Office spokeswoman says refugees who enter Britain after applying for asylum in another country will be sent back.
French authorities have given 908 refugees permits allowing them to apply for political asylum. Their ship ran aground on the Cote d'Azur on Saturday.
The British Government is pressing the French to register the refugees' claims as quickly as possible.
Some of the refugees have said they want to travel to Britain.