08:13

Boris Johnson told David Cameron that more was needed to win his support in the referendum campaign, writes Nicholas Watt.

Nothing had changed, the mayor is said to have remarked and reportedly added that more was needed.

A source close to the mayor said he would live up to his commitment to outline his position on the EU “with deafening eclat” on Friday if the prime minister secures a deal at the EU summit, which opens in Brussels on Thursday afternoon. The source said: “The mayor will make everything abundantly clear by the end of the week if the prime minister gets a deal on Friday. He is genuinely undecided.”

Johnson told Cameron more work was necessary on his plan to assert parliament’s sovereignty. Oliver Letwin, the prime minister’s policy chief, has been tasked with outlining measures to deliver on his pledge to put that issue “beyond doubt”.

Cameron’s vow in the Commons earlier this month came after Johnson asked him to explain how his EU reforms would “assert the sovereignty of this House of Commons and these Houses of Parliament”. Cameron replied: “I am keen to do even more to put it beyond doubt that this House of Commons is sovereign. We will look to do that at the same time as concluding these negotiations.”

Letwin is understood to be examining two ways to deliver on this pledge:

A declaration that the UK supreme court or another official body would have similar powers to those of the German constitutional court, which has the right to assess whether legal acts by the EU’s institutions remain within the scope of the powers of the EU.

An amendment to legislation to make clear that the UK’s agreement to the primacy of EU law – which dates back to 1972 – was gifted by parliament and could therefore be withdrawn by parliament.

Johnson’s talks with the prime minister mainly focused on the sovereignty of parliament because that is a matter that rests entirely with the UK government and is not part of the EU negotiations. But Downing Street believes it has to chart a careful course to win over Johnson without alarming EU leaders who may fear that Britain is seeking to overturn one of the key principles of the EU – the primacy of EU law.



The London mayor also asked the prime minister about the state of the negotiations on restricting in-work benefits, asserting the role of national parliaments, giving Britain an opt-out from the EU’s commitment to ever closer union and promoting competitiveness. But the EU negotiation package was not the main part of their discussions because the mayor accepts that he can bring the greatest influence to bear on asserting the sovereignty of parliament.