France issues border checks warning to Britain

A senior French minister has warned that his country could tear up a treaty allowing British border police to operate in the port city of Calais if it left the European Union (EU), the media reported on Thursday.

France's economy minister Emmanuel Macron said the "Le Touquet" agreement -- a bilateral relationship between Britain and France -- would be threatened by Brexit (Britain's EU exit), The Guardian reported.

The Treaty of Le Touquet is an agreement between France and Britain that has been in place since 2003 and governs border control arrangements and immigration.

The comments came as British Prime Minister David Cameron prepared to travel to France for a summit, raising the prospect of the "Jungle" refugee camp being relocated to Britain in the case of Brexit.

There are currently believed to be about 4,000 migrants amassed in Calais, hoping to cross to Britain.

Cameron and French President Francois Hollande will address the Calais refugee crisis later on Thursday.

The prime minister has claimed that thousands of refugees will end up on the Kent coast if Britain leaves the EU.

He said France would respond to a Brexit vote by saying it was tearing up the bilateral treaty that allows police officers from both countries to work across the Channel.

Speaking before the meeting, Cameron said EU membership gave Britain "greater security and greater capacity to project power globally".