Brexiteer and leader of the House of Commons Andrea Leadsom has said the legal default position is the UK leaving the bloc without a deal if Prime Minister Theresa May’s agreement is voted down in the House of Commons next month.

“Parliament can always of course express a view, but in order to avoid a no-deal Brexit, Parliament does need to vote for a deal,” Mrs Leadsom said in an interview with The Telegraph.

“The legal default position is that if there isn’t a deal then the UK leaves the EU in March 2019 without a deal,” she made clear, after a cross-party group of Remainer MPs tabled an amendment to the finance bill that would only allow a no-deal exit from the EU if MPs voted for it.

“The Government will have to, as a competent Government, continue to prepare for all eventualities,” she added in relation to the Government confirming this week it would ramp up no-deal preparations.

“That is Government policy.”

The House of Commons leader is said to favour the “managed no deal” option if May’s deal is rejected, where the UK would leave the EU with a transition period while making a number of individual, temporary deals in areas such as aviation and transport.

Last week, Mrs Leadsom hit back at suggestions by Remain-voting Cabinet minister Amber Rudd that there could be a “plausible argument” for a second referendum if May’s agreement, which could see Northern Ireland locked in regulatory alignment with the EU and threaten the Union, is voted down in January.

“Failing to deliver on the referendum, or suggesting that people rethink it and try again, would be unforgivable,” Leadsom told The Telegraph.

“Not only for the fact that it ignores the clear result of the biggest democratic exercise ever, but also because of what would be the potential knock-on effect,” she said, adding it would “totally undermine people’s faith in our politics and our democracy” and result in loss of support for the Conservative Party.

Senior business leader John Longworth has said that the UK will prosper if it leaves the EU with no deal and trades on World Trade Organization (WTO) rules, with European governments and even the EU’s executive arm already planning for the UK to make a clean break.

Other mechanisms are in place to minimise trade disruption after the UK signed up to continued membership of the Common Transit Convention (CTC), which reduces disruption when hauliers are travelling through multiple countries.

The UK could also trigger Article 24 of the WTO’s rules, which allows for the negotiation of free trade agreements between Brussels and Brexit Britain with zero tariffs for up to ten years.