Ministers have been branded “petty” and warned security cooperation could be affected by a reported plan to withhold full diplomatic status from the EU’s ambassador in London.
Downing Street has not denied it is withholding certain privileges from Joao Vale de Almeida that are afforded to other countries’ ambassadors.
Prime Minister Boris Johnson’s spokesman said the EU was “a collective of nations, not a state”.
But the government was accused of breaking precedent and being out of step with the 142 nations who do give EU diplomats the same rights as those from other countries.
Lord Gavin Barwell, Theresa May’s former Number 10 chief of staff, said it was “difficult to understand why the government is refusing to give EU diplomats full diplomatic status” and called the decision a “mistake”.
He said “we used to support this” and “every other country does it”, adding that when the post-Brexit trade deal was struck on Christmas Eve, Mr Johnson “spoke warmly about what close friends we would be”.
David Lidington, a former Conservative de facto deputy prime minister who now chairs the RUSI defence think tank, added he really hoped the government won’t “pick a fight on this”.
He warned it could set a “bad precedent” for regimes that “hate EU ambassadors speaking up for human rights defenders”.
A senior Tory MP, chair of the Commons defence committee Tobias Ellwood, also branded the decision “simply petty”.
He tweeted: “Biden commits to strengthening alliances and we engage in silly spats which will not help strengthen security and trade cooperation. We are better than this.”
Labour frontbencher Wes Streeting called it “Trump politics in a Biden era”.
Defending the position, Mr Johnson’s spokesman told reporters on Thursday that the Foreign, Commonwealth and Development Office (FCDO) was “continuing to engage” with Brussels on the issue.
The FCDO said in a statement: “The EU, its delegation and staff will receive the privileges and immunities necessary to enable them to carry out their work in the UK effectively.”