French president Emmanuel Macron is adamant that Brexit cannot be delayed beyond December 2019, and will ask the other 26 European Union leaders to impose compliance checks on the UK every three months during any extension, according to diplomatic sources who have been privately briefed on his thinking ahead of this week’s emergency European Council summit of EU leaders.

As Macron prepares to meet Theresa May in Paris on Tuesday ahead of Wednesday’s meeting, the sources told BuzzFeed News it was extremely unlikely that Macron would block an extension outright.

Instead, he will look to bind any UK government into stringent terms and seek a firm commitment from his fellow leaders that they will stick to whatever decision is agreed this week, rather than dither further down the line, even if that might mean no deal.

BuzzFeed News reported on Monday that the EU will expect the UK to meet “enhanced sincere cooperation” terms in an attempt to allay fears that if May’s successor is a hardline Brexiteer, they will be unable to disrupt the EU’s decision-making on budgets and other key issues. Brussels will reserve the right to end the extension period early, in agreement with the UK, in the event of noncompliance with this duty.

But Macron will ask his European counterparts to go even further, the diplomatic sources explained.

In addition to seeking a commitment from the UK that it will not disrupt the EU’s working, he wants the delay to be structured around quarterly checkpoints to confirm the extension, with the possibility of terminating early — in June or September — if the UK is found to not be respecting its commitments.

Macron also wants to deny the UK the right to appoint a commissioner to the next European Commission.

The Élysée declined to comment on Macron’s position when approached by BuzzFeed News on Tuesday, pointing out that he had yet to meet May and that the European Council meeting had not yet taken place.