BORIS Johnson has been accused of making a “mockery” of British-French relations, and been told he must “take responsibility” for the migrant crisis following last week’s fallout.

France’s interior minister Gerald Darmanin said the Prime Minister had acted in a “peculiar” fashion by opting to post on Twitter a letter to French president Emmanuel Macron outlining his proposed solutions to the small boat crossings in the Channel.

Paris was so enraged by the publication of the letter that it opted to withdraw the invitation for the UK to join weekend talks with other European ministers about how to stem the flow of people across the strait.

READ MORE: 'Don't communicate via tweets': French president pans Boris Johnson over Channel crossings

Counterparts from France, the Netherlands, Belgium and the European Commission met in Calais on Sunday, but neither Home Secretary Priti Patel nor British officials were present after being told they were not welcome.

The Prime Minister’s letter to Macron had come after a dinghy capsized in the Channel Sea on Wednesday, claiming 27 lives.

Darmanin said the British leader had looked to make a “mockery” of France by, according to the minister, urging Paris to “take back their migrants”.

Speaking to BFMTV, Darmanin said: “When there are serious diplomatic exchanges … and lives that are at stake … and some minutes later you see that a letter, which no-one has ever mentioned before, is published on Twitter from the British Prime Minister to the President of the French Republic before the President of the Republic has received it, it’s a bit peculiar.

“When in this letter the English say the French should ‘take back their migrants, all their migrants’, it’s a mockery.”

He added that British-French relations were not currently “normal” and that “our private exchanges are not always in line with our public exchanges”.

The senior French politician also tweeted on Monday, urging the British Government to “take responsibility” for the migrant crisis.

No10 has previously looked to play down talk of a bilateral rift.

After talks on Sunday, it was agreed that a plane, operated by European Union border agency Frontex, will monitor the shores of the Channel for people crossing from December 1.

Migration officials also pledged to work together more closely against people-smuggling networks and the trade in inflatable boats.

Patel was understood to be pleased with the decision to dispatch the Frontex plane.

Among the dead after Wednesday’s tragedy was said to have included a pregnant woman, children and a 24-year-old Kurdish woman from northern Iraq trying to reunite with her fiance.

It was the highest death toll on record in the current crisis.