Boris Johnson used his keynote address at the Conservative Party conference to brutally mock the EU's former chief Brexit negotiator Michel Barnier. The Prime Minister told Tory MPs and cabinet members in Manchester it was a "sublime irony" that Mr Barnier was now backing a referendum on immigration in France amid concerns over a loss of sovereignty to the EU.

       Mr Johnson said: "Is it not a sublime irony that even in French politics there is now a leading centre-right politician calling for a referendum on the EU.

       "Who is calling from France to reprendre le control.

       "It is good old Michel Barnier!

       "That is what happens if you spend a year trying to argue with Lord Frost."

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       "The greatest frost since the Great Frost of 1709," boasted the Prime Minister.

       It comes after Mr Barnier kick-started his French presidential bid with a call for a referendum on "immigration" and "legal sovereignty."

       The 70-year-old announced: "On immigration, we must regain our legal sovereignty to no longer be subject to the judgments of the ECJ or the ECHR.

       "We will propose a referendum in September [2022] on the question of immigration."

       On Tuesday evening Lord Frost expressed his surprise at Mr Barnier's eurosceptic turn in a speech to Conservative conference

       "I am a bit surprised by it," he said.

       "His sort of cherrypicking of EU legal framework, which is obviously a bit unusual given where he started."

       Lord Frost also offered a review on Mr Barnier's new book on the Brexit negotiations.

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       "I've sort of skim-read the French version but I haven't seen the English version yet," said Lord Frost.

       "It's quite a good read actually.

       "Negotiations are quite dull for those who are not actually involved in them.

       "I think it's quite hard to make an interesting book about them, but he has actually conveyed some of the mood from the bits I was involved in."