The prime minister’s spokesperson said a new session of parliament – due to get under way in June – would not begin until the withdrawal agreement had been ratified.

“That is part of the current Queen’s Speech cycle and we need to finish that work,” he said, admitting there was “no specific date” for a new session.

The determination to deliver Brexit first opens up the prospect of no Queen’s Speech until the autumn at the earliest – even if the prime minister survives that long.

Although talks with Labour will restart today, both sides are gloomy about progress after trading accusations that neither is prepared to make any meaningful compromises.

Many at Westminster believe Ms May is desperate to avoid a new Queen’s Speech for fear that Brexiteer Tories will vote it down – to bury the deal they hate – and accelerate her departure from No 10.

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A new session would also require a new negotiation for the Democratic Unionist Party to continue propping up the Tories in power, amid acrimony in relations with the Northern Ireland party.

However, delay will open up accusations of a “zombie government”, because no other major legislation is in the pipeline.

The Queen’s Speech traditionally takes place annually, but a two-year session was announced in June 2017 because of the enormity of carrying out EU withdrawal.

Asked if it would be delayed until Brexit was “over the line”, Ms May’s spokesperson replied: “What we are focused on is the withdrawal agreement bill because that is the legislation necessary in order to ratify our withdrawal from the EU.”

He denied Ms May now led a zombie government, telling journalists: “I don’t accept that.”

He pointed to recent announcements on tackling knife crime and protecting children online, as well as the billions of extra investment going into the NHS.

However, the government has pulled back from introducing the withdrawal agreement bill, despite that failure ensuring the European parliament elections will go ahead on 23 May.

Ms May knows that, without an agreement with Labour, the bill will be thrown out – which would force her to begin a new session, with all the dangers that poses.

The spokesperson was unable to say that the government would bring any fresh proposals to the talks, or even whether the key controversy of a customs union would be discussed.

He refused to set a deadline for abandoning the cross-party effort, amid suspicions it is in neither party’s interest to pull the plug, even if no progress is being made.

Downing Street is believed to have drawn up a list of second-tier legislation to justify extending the session beyond the original two-year deadline.