One of Britain’s harshest EU critics over Brexit is set to become German foreign minister and could challenge Angela Merkel for the chancellorship after he quit Brussels to return to national politics.

In a move that could have far-reaching consequences for the Brexit negotiations, Martin Schulz announced on Thursday he would not seek re-election as president of the European parliament.

While that will remove one of Brexit’s toughest opponents from the Brussels hierarchy, Mr Schulz is likely to have even more influence on negotiations from Berlin.

He is widely expected to be named German foreign minister early next year when the incumbent, Frank-Walter Steinmeier, takes over as German president.

And it is thought he may seek his party’s nomination to take on Mrs Merkel as chancellor in elections at the end of next year.