LONDON — Boris Johnson’s Brexit strategy faced a fresh obstacle on Monday when his bid for a new vote was knocked back by House of Commons Speaker John Bercow.

But Bercow’s ruling could be just a hiccup. Johnson’s government said it will press on with its effort to get Britain out of the European Union at the end of the month. 

Number crunchers say Johnson may have the votes to narrowly get approval for the deal he negotiated with his European counterparts, though amendments may complicate its passage.

Citing parliamentary convention, Bercow said Parliament would not vote Monday on the deal, because the government’s motion was “in substance the same” as the one lawmakers had considered during their “Super Saturday” session.

“The motion will not be debated today, as it would be repetitive and disorderly to do so,” Bercow said.

Bercow — an unusually colorful speaker who has played a starring role in the Brexit drama — has been accused periodically of an anti-Brexit bias.

“It is becoming remarkable how often you please one lot and not the other lot,” Conservative lawmaker Bernard Jenkin said Monday.

But the speaker made “absolutely no apology” for his ruling.

“Nothing in what I have said in any way impinges upon the opportunity for the government to secure approval of its deal,” he said, adding that it is “not for the speaker to interfere.”

On Saturday, when presented with Johnson’s Brexit deal, Parliament voted to withhold support until all the supporting legislation had passed. That vote triggered another law requiring Johnson to send a letter to the E.U. asking for a Brexit delay until Jan. 31.

Johnson, who earlier said he would “rather die in a ditch” than ask for an extension, sent multiple letters to the E.U. on Saturday night. He sent one, unsigned, asking for an extension, and a second letter and a cover letter making it clear he was against it.

E.U. diplomats in Brussels told The Washington Post they will watch developments unfold in Britain before deciding on the delay request.

Monday’s setback was not a “crippling problem for Number 10,” said Simon Usherwood, a politics professor at the University of Surrey, referring to 10 Downing Street. “But it underlines the depths of mistrust between the executive and the legislature at the moment.”

Attention now shifts to the withdrawal agreement bill, the legislation needed to implement the Brexit deal into British domestic law.

On Tuesday, Parliament is expected to vote on whether to move the bill forward. It will not be a line-by-line consideration — that comes later — but rather an overall vote on whether Parliament is happy to proceed to the next stages. The result will be watched closely as an indication of where things stand.

Usherwood said support at the initial stage “starts large, and, as people get into the weeds of it all, it gets smaller. So if tomorrow it passes by just one or two votes, it’s a sign of real difficulty ahead” for the government.

Opposition parties are preparing amendments that include proposals to keep Britain in the E.U. customs union or require a “confirmatory vote” on the deal — essentially a second Brexit referendum.

Johnson and his allies view such proposals as designed to thwart Brexit — to delay approval of Johnson’s deal or make it unacceptable to the Conservative Party or to the E.U. The pro-Brexit tabloid newspapers have called the opposition-party moves acts of “sabotage.”

Justine Greening, a former Conservative minister, said she would back an amendment for a second referendum because things have changed since the 2016 vote, when Britons opted 52 percent to 48 percent to leave the E.U.

“We’re 3½ years on from Brexit,” she said, “and I think whatever happens, it feels like we are a very long way away from the lofty ideals of that campaign.” 

Meanwhile on Monday, a Scottish court delayed a decision on whether Johnson complied with the law to seek a Brexit extension with his multiple letters and unsigned document.

David Pannick, a lawyer who represented campaigners who took Johnson to court over his suspension of Parliament, told the BBC on Monday he thought Johnson was “on the right side of the law — just about — on this occasion.”