LONDON, July 13 (Reuters) - Former London mayor Boris Johnson was appointed as British foreign minister by the country's new Prime Minister Theresa May on Wednesday.

Johnson was a leading figure in the victorious "Leave" campaign in Britain's European Union membership referendum last month.

His role in Britain's negotiations over its future relationship with the EU is likely to be limited because May is expected to create a new ministerial post focused on Brexit. (Writing by William Schomberg; editing by Stephen Addison)