Brussels and the UK will press ahead with trade talks starting on Tuesday in Brussels even as both sides refuse to concede any ground over Boris Johnson’s plan to introduce new legislation which overrides his Brexit divorce treaty.

Maros Sefcovic, the EU commissioner in charge of overseeing last year's withdrawal agreement, on Monday said Brussels would “not be shy” in legally pursuing the UK once an end of September deadline passes for the UK prime minister to rewrite his internal market bill.

“We maintain that the bill, if adopted in its current form, would constitute an extremely serious violation of the protocol, as an essential part of the withdrawal agreement, and of international law,” Mr Sefcovic said after a meeting with the UK’s cabinet office minister Michael Gove in Brussels.