The next Conservative leader has been urged to scrap MPs’ four-week break for party conference season and told it would be “immoral and insulting” to go “missing in action” during the worsening cost of living crisis.

With the Commons due to go into recess for a month in mid-September for the parties’ annual conventions, ministers were encouraged to remain in Westminster to devise and debate emergency plans for supporting struggling people through the winter.

The Liberal Democrats kick off conference season in Brighton from 17-20 September, followed by Labour in Liverpool from 25-28 September. It is then the turn of the Conservatives in Birmingham from 2-5 October, before the SNP’s runs from 8-10 October in Aberdeen.

MPs will not be sitting in parliament for almost the duration, with the Commons in recess from 22 September until 17 October, meaning there will be no debates, no new legislation tabled, and no chances to question senior government figures across the dispatch box.

While MPs will still be able to continue working, holding private meetings with ministers or with constituents, the scale of the economic crisis facing the country has prompted the campaigner Gina Miller to call on Rishi Sunak and Liz Truss to pledge to cancel the conference recess.

She said she was “truly staggered” that the break was still set to go ahead. She said the UK had “endured an administration of the undead over the summer recess”, so “further delay is inexcusable”.

Miller said party conferences “do not serve the people or the public interest” but were instead “shindigs for fans” where attenders “buy influence and make cosy deals”.

Writing to the two Conservative leadership contenders, Miller said: “As the candidates for prime minister, you should urgently speak to the leaders of other parties and agree conference recess will be cancelled so MPs can work on the immediate challenges facing the country.”

Miller, who set up the True and Fair party, said the Commons should sit for a minimum of 40 weeks a year and criticised politicians for “partying whilst millions face destitution”.

She said: “You should be spending your time working for the people of the UK who elect and pay for you, not your party’s members.”

When parliament is not sitting, the government can ask the Commons Speaker to order a recall. However, such events are rare and usually happen only for a single day in the event of an emergency. The last recalls have been to pass emergency Covid laws, to discuss the fall of Afghanistan to the Taliban, and after the death of Prince Philip.

Truss and Sunak’s campaign teams were contacted for comment.