France has formally rejected Boris Johnson’s call for British authorities to conduct joint patrols on the beaches around Calais to deter migrants from crossing the Channel.

In a letter to Mr Johnson, French Prime Minister Jean Castex said “we cannot accept” the presence of British police or soldiers as it would compromise the sovereignty of the nation.

He also suggested that the UK should reform its systems to provide “legal immigration routes” for those wishing to come to the country instead of risking the perilous crossing.

But he promised that France would examine “in good faith” some of the proposals put forward to get out of the crisis.

The British Prime Minister sparked fury in France by issuing his letter to President Emmanuel Macron calling for further action in the wake of the tragedy that saw 27 people lose their lives attempting to cross the English Channel in November.

The bitter feud saw reports that Mr Macron called Mr Johnson a “clown” and a “knucklehead”.

But the British government has promised to work in “close cooperation and partnership” with France following Mr. Castex’s letter.

According to Le Monde, Mr Castex wrote: “We have always agreed to examine and discuss in good faith the British proposals for strengthening and cooperation.

“We have accepted some, we have refused others.”

Mr Johnson had suggested that border forces officers, or failing that private security contractors, could be deployed on joint patrols.

Mr Castex sad: “We cannot accept, for example, that British police or soldiers patrol our coasts.

“It comes from our sovereignty.

France has repeatedly refused British requests for joint land and sea operations on its territory.

The French prime minister said more than 700 police and gendarmes were already covering the area around Dunkirk and Calais to prevent small boats carrying migrants from taking on water.

But these efforts “only allow us to contain the phenomenon, not to provide a lasting response”.

To do this, he suggested that the UK should open up legal immigration channels for those who have legitimate reasons to enter the country, and pursue a “more effective” return policy for those who do. not.

A UK government spokesperson said: ‘The devastating events of the past week were a tragic reminder of the dangers of these crossings and, like our French neighbors, the UK government is determined to prevent further loss of life in the English Channel. .

“We are ready to discuss all options in the spirit of our close cooperation and partnership, and as a shared global challenge, it is vital that we tackle illegal migration collectively and urgently. “

Relations between the governments of London and Paris have been soured by the issue of migrants and post-Brexit fishing permits.

According to Le Canard Enchaine, Mr Macron launched his “closed-fist” attack on the prime minister in a private conversation with a small group of assistants during a visit to Croatia last week.

He said the Prime Minister was seeking to make France a “scapegoat” for Brexit, which had proved “catastrophic” for the United Kingdom.

An official UK government source said Mr Johnson was a ‘strong public defender’ of a strong cross-Channel relationship and ‘our approach will not change even if we have to wait until the other side of the French presidential election for a change. of your “.