It also raised cries of betrayal among members of the Democratic Unionist Party, which backed the Conservative government throughout Brexit. On Wednesday, in the face of a no-confidence vote, the party’s leader, Arlene Foster, paid the price for that policy, announcing her resignation, effective May 28.
The European Parliament had delayed its vote to protest Britain’s handling of Northern Ireland and the protocol. Britain’s actions are the source of a legal complaint filed by the European Commission, the bloc’s executive, after Britain unilaterally extended grace periods for not conducting checks on goods being transported between Northern Ireland and the rest of Britain.
That mistrust ran through the debate over the trade deal, called the Trade and Cooperation Agreement. Christophe Hansen, a key legislator on Brexit from Luxembourg, said that a positive vote “should not be seen as a blank check to the U.K. government or a blind vote of confidence in that they will implement the agreements between us in good faith, but it is rather an insurance policy from our perspective.”
The agreement, Mr. Hansen said, “will help us remind the United Kingdom of the commitments it has signed up to.”
Manfred Weber, a German who heads the largest party grouping, the center-right European People’s Party, put it bluntly on Twitter. “We will vote in favor of the post-Brexit T.C.A.,” he wrote, referring to the trade agreement. “But we are concerned about its implementation, because we do not trust Boris Johnson’s government.”
There were also numerous worries expressed about Britain’s misusing or undermining the complicated arrangements on fishing rights.
David McAllister, a German legislator who is half Scottish, dismissed some of the problems as teething issues. But he said that some derived from “the kind of Brexit the U.K. has chosen for itself,” which will mean increasing divergence from the European Union single market. That by itself will require continuing discussion, he said, as well as working through areas left out of the Brexit deal, including financial services and foreign and security policies.