Jeremy Corbyn has sought to exploit divisions in the Conservative party over Brexit by pressing Theresa May at prime minister’s questions for more details on the deal she hopes to strike with the EU.

The Labour leader, who has sometimes been criticised for not scrutinising the government’s Brexit policy robustly enough, devoted all his questions to the issue.

As May’s ministers prepare for a Brexit awayday at her country retreat of Chequers to thrash out their differences, Corbyn asked: “Could the prime minister take the opportunity to tell the house and the country what is the government’s desired Brexit outcome?”

An unruffled May shot back: “I’m very happy to: a bespoke economic partnership.”

Corbyn highlighted what he claimed was a weakening of language between May’s Lancaster House speech, when she said the government would seek “tariff-free access” to the single market, and more recent statements that trade should be “as frictionless as possible”.

He also mocked David Davis’s speech on Tuesday, when the Brexit secretary tried to reassure the public that the government would not seek to slash regulation after Brexit and turn Britain into a “Mad Max dystopia”.

“Doesn’t she think he could set the bar a bit higher than that?” Corbyn asked.

May insisted “this is a government that will not only protect workers’ rights, but enhance workers’ rights”, and listed a series of measures she has taken, including commissioning the Taylor review of how to enhance employment rights in the gig economy.

But Corbyn pointed to the letter sent to the prime minister by the influential European Research Group of pro-Brexit backbenchers, who urged her to ensure that Britain would not be a “rule-taker”. “Sixty-two of her backbenchers want a bonfire of regulations, want to destroy workers’ rights in this country,” Corbyn said.

Labour’s frontbench have made a series of interventions on Brexit in recent days, with Corbyn suggesting in a speech on Tuesday that Labour now believes a customs union with the EU is the best way of preventing a hard border in Northern Ireland.

Previously, Corbyn’s team had only suggested a customs union as a “viable option”, not their desired outcome.

The shadow Northern Ireland secretary, Owen Smith, said Labour’s position was “evolving and deepening”.

At the start of PMQs, the Speaker of the House of Commons, John Bercow, upbraided MPs for their rowdy behaviour.

“Let’s try to behave properly in these sessions: that means listening to the questions, and listening to the answers,” he said.

This article was written by Heather Stewart Political editor, for on Wednesday 21st February 2018 13.27 Europe/London © Guardian News and Media Limited 2010