Pressure is building on Theresa May to release 58 secret studies into the economic damage from Brexit, as a “binding vote” looms in the Commons.

Labour believes it is found an ancient Parliamentary procedure that can force the Prime Minister to end her suppression of the findings.

It comes as the number of MPs demanding the release of the information reached 178. Campaigners have also threatened legal action.

The studies cover experts’ verdicts of the likely impact of different scenarios for leaving the EU on different sectors comprising no less than 88 per cent of the economy.

Now Labour says it has found a way to prevent the Government ignoring a defeat on an issue on the Commons floor – as it did recently over the universal credit shake-up.

Parliamentary rules, dating back to the 19th century, say MPs have the power to demand papers “which are in the possession of ministers” by passing a motion.

Theresa May refuses to guarantee MPs vote on Brexit deal before Britain leaves EU

The idea is that the studies would be released to the Brexit Select Committee, which would review them and decide which information should be put in the public domain.

Crucially – because Erskine May, the parliamentary bible – regards such a vote as binding, the Conservatives will not be able to sit on their hands when it is staged on Wednesday, Labour says.

It means the Tories, lacking a Commons majority, are likely to require the support of the Democratic Unionist Party, in order to win.

Brexit: the deciders Show all 8 1 /8 Brexit: the deciders Brexit: the deciders European Union's chief Brexit negotiator, Michel Barnier Getty Brexit: the deciders French President Emmanuel Macron Getty Brexit: the deciders German Chancellor Angela Merkel Reuters Brexit: the deciders Commission President Jean-Claude Juncker EPA Brexit: the deciders The European Parliament's chief Brexit negotiator Guy Verhofstadt Getty Brexit: the deciders Britain's Prime Minister Theresa May Getty Images Brexit: the deciders Britain's Chancellor of the Exchequer, Philip Hammond PA Brexit: the deciders After the first and second appointed Brexit secretaries resigned (David Davis and Dominic Raab respectively), Stephen Barclay is currently heading up the position PA

Sir Keir Starmer, Labour’s Brexit spokesman, said: “Ministers cannot keep withholding vital information from Parliament about the impact of Brexit on jobs and the economy.

“At the start of the negotiations, Theresa May said everyone needed certainty during the Brexit process and that the vote to leave was a vote for Parliament to take back control.

“If those words meant anything at all, then she should stop sidelining Parliament and give MPs the information they need to properly hold the Government to account in what are undoubtedly the most important negotiations since the Second World War.”

Ministers have insisted they cannot publish the studies because doing so could weaken the UK’s negotiating position, but the argument has been widely dismissed.

There was ridicule when the Department for Exiting the European Union (DexEU) claimed those negotiations had to be conducted in a “safe space”.

The Treasury Select Committee, chaired by former Conservative cabinet minister Nicky Morgan, is also expected to discuss whether its members should be allowed to see the findings.

And Seema Malhotra, the Labour MP, will appeal against a refusal to provide the reports – into everything from food prices, tourism and banking to aerospace, pharmaceuticals, oil and steel – under the Freedom of Information Act.

Sir Vince Cable, the Liberal Democrat leader, added his voice to the criticism, saying: “The Government is desperately trying to hide the true impact of an extreme Brexit from the public.

“Ministers need to come clean and publish these reports immediately.”

The news comes as 178 MPs from five political parties called on the Government to release the reports, The Independent can reveal.

Dominic Grieve, former Attorney General and the Tory MP for Beaconsfield, is one of those who is urging the Government to make the contents of the 58 studies public and said he “believes the release of the Brexit Impact reports would be most desirable”.

Caroline Lucas, co-leader of the Green Party, said it was “completely unacceptable” for the public to not be given all the information from the reports.

“The Government must stop hiding behind this veil of secrecy and release these reports immediately. Ministers love to talk about how they are handing power to people by pursuing Brexit – yet they refuse to be honest about the potential impacts of this process. Such secrecy utterly betrays the trust of the British people,” Ms Lucas told The Independent.

“It’s completely unacceptable that people aren’t being given the full facts, and I urge ministers to release these reports now.”

Eloise Todd, CEO of Best for Britain, the political campaign group that compiled the list of MPs, urged parliamentarians to “vote for transparency and democracy”.

“The public has been asking MPs from all parties to release these studies, all of which have been paid for by taxpayers’ money and which contain essential information about the costs and risks of Brexit.

“The fact a vote had to be called to force the release of these studies shows just how under threat our democracy has become. Citizens across the UK will be watching how their MPs vote – and we’ll make sure we tell them. MPs from all parties must make the right choice and vote for transparency and democracy and release the Brexit reports.”

The Government had initially chosen not to release a list of the 58 sectors where studies have been carried out, until finally doing so on Monday night.

A DexEU spokesman said: “There is a strong public interest in policymaking associated with our exit from the EU being of the highest quality and conducted in a safe space to allow for design and deliberation to be done in private.”

Ministers also claim that Parliament voted to keep under wraps any documents that could undermine attempts to negotiate the best deal for Britain.

But Labour has seized on an extract from Erskine May that states: “Each House has the power to call for the production of papers by means of a motion ... the power to send for papers by means of a motion for unopposed return extends to papers which are in the possession of ministers or which ministers have the authority to obtain.”