In an incredible warning to the President, Mr Barnier stated France must understand why Brexit occurred. Although France is one of the leading states of the EU now the UK has left, the Brexit negotiator claimed Frexit may well occur in the future. In a speech to the French Senate today, he said: “We must take a little time to understand why Brexit happened.

“Why was there this rejection of the European Union?

“In many poor or troubled parts of the UK, the industry has disappeared, and that also happens here.

“There are fewer public services, the feeling of not being protected.

“This is a popular feeling that I recommend listening to.”

In a general attack on the EU, Mr Barnier revealed Brussels had been ignorant to the rise of Euroscepticism in the bloc.

In a further warning to Mr Macron, the negotiator revealed his desire to return to domestic politics after being released from his EU duties.

He added: “You will not have to wait much, if I may say so, because as soon as I am released from my European responsibilities, I will resume my part, with determination, in the French political debate.”

Mr Barnier spoke to the senate, nearly two months since he agreed the Trade and Cooperation Agreement.

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Although the protocol was created to ease trade between Great Britain, Northern Ireland and the EU, many have stated the increased customs checks have damaged businesses on the island of Ireland.

Cabinet Office minister Michael Gove met with his EU counterpart and vice-President Maros Sefcovic, last week to discuss matters.

In order to ease trade issues, Mr Gove had asked for an extension on the grace period for goods travelling between Great Britain and Northern Ireland.

Prior to the meeting last Thursday, however, Mr Sefcovic claimed the UK had not applied the protocol properly.

Due to this, he argued the protocol cannot be changed as the two agreed to spare no effort in implementing solutions to the legislation.

Commenting on the protocol, Mr Barnier labelled the agreement as the solution to issues rather than the cause.