Labour accused Theresa May of a “great stitch-up” after the government announced that ministers would be given 12 weeks to respond when they are defeated on motions raised by the opposition.

Andrea Leadsom, the leader of the House of Commons, said on Thursday she would take up a proposal made by the veteran Eurosceptic MP Peter Bone for a minister to be obliged to issue a response within 12 weeks whenever the government lost an opposition day debate.

“Where a motion tabled by an opposition party has been approved by the house, the relevant minister will respond to the resolution of the house by making a statement no more than 12 weeks after the debate,” she said in a written statement to parliament.

“This is to allow thoughtful consideration of the points that have been raised, facilitate collective discussion across government, especially on cross-cutting issues, and to outline any actions that have been taken.”

But Jon Trickett, the shadow minister for the cabinet office, dismissed the concession and accused the government of trying to bypass parliamentary scrutiny.

“The government’s contempt for parliament and democracy is disgraceful,” he said. “After failing to win a majority at the general election, the Tories have engaged in one stitch-up after another. They’ve fixed standing committees in their favour, are attempting to grant themselves sweeping powers with the EU withdrawal bill, and now seem to have confirmed they will ignore the decisions of parliament on opposition day debates, in a cynical attempt to push through policies like the botched rollout of universal credit.

“Their great stitch-up proves that this is is a weak and divided government, led by a prime minister who is in office but not in power.”

Labour has been exploiting May’s fragile majority to raise pressing social issues, including universal credit and university tuition fees.

A motion tabled by the party calling for the universal credit rollout to be paused was passed unanimously last week, as almost all Tory MPs abstained – some of them reluctantly.

The government has been forced into a series of concessions as May adjusts to governing without a stable majority. David Gauke, the work and pensions secretary, announced last week that charges would be abolished for the universal credit helpline, an issue raised by Labour.

On Wednesday, as Labour prepared to debate the impact of changes to housing benefit on supported housing, May announced a climbdown at prime minister’s questions.

Neither the supported housing motion, nor a separate one on cuts to social care, was forced to a vote by Labour; but it believes it can continue to highlight the unpopularity of key areas of Conservative policy.

On universal credit, some potential Tory backbench rebels suggested they had been given private reassurances by the prime minister of further concessions to come.

Philip Hammond’s budget, which will be delivered on 22 November, could be another potential flashpoint if he chooses to implement controversial policies in the search for extra revenue.

Even before the general election, when May had a comfortable majority, the chancellor was forced to abandon a planned increase to national insurance for the self-employed after a backlash from backbenchers.

Valerie Vaz, the shadow leader of the Commons, complained there was a lack of consultation over legislation, and accused Leadsom of treating parliament like “House of Games”—a combination of House of Cards and Game of Thrones.

“The government should get their house in order and deal with the democracy of why we are here. We are elected as representatives to speak on behalf of our constituents,” she added.