Former deputy Prime Minister Nick Clegg has suggested there is an “inner Remainer” within Theresa May as he recalled her warnings of the perils of Brexit during the 2016 referendum.

Speaking on the eve of Article 50 being triggered by the Prime Minister – triggering Britain’s withdrawal from the EU – the former Liberal Democrat leader encouraged the public to read Ms May’s speech during the referendum campaign.

“There was a speech by a prominent Conservative, which as one of the most thoughtful and thorough arguments I’ve read in a long time in favour of our continued membership of the European Union,” Mr Clegg said.

He added: “It was a thoughtful exposition about the constraints on sovereignty. It was delivered by Theresa May less than a year ago – it’s well worth reading.

“So I guess the question that hangs over all of us is either she didn’t believe a word she said or there is still an inner remainer within her soul struggling to come out – and she’s just been forced by circumstances to do something contrary to her view.

"It's either an act of spectacular insincerity when she said those words or she is acting diametrically contrary to her stated and - in my view - very thoughtfully expressed views about Britain's role in Europe of less than a year ago."

His comments came at an event hosted by Open Britain, a campaign group against a hard Brexit, alongside Nicky Morgan, the former Conservative Education Secretary and Labour’s Chris Leslie.

When asked whether they had “allies” in Government willing to resist mounting right-wing pressure from the UK to quit the EU without a deal, Ms Morgan replied: “In terms of allies in Government, I can't give you names and I don't know whether others are having discussions, but yes, there are absolutely members of the Government who very much want a deal, who were staunch Remain campaigners and will appreciate the importance of things like [maintaining] the exact same benefits that we currently get in the single market."

The senior MPs also published a document outlining ten promises made to the British people by the Government or by Vote Leave during the EU referendum campaign.

They include the pre-referendum pledge to provide the NHS with an extra £350m a week, delivering the “exact same benefits” as the UK currently has within the single market and customs union, and no changes to the border between Northern Ireland and the Republic.

The unveiling of what they describe as the “Brexit contract” comes as the Prime Minister prepares to invoke Article 50 of the Lisbon Treaty, triggering Britain’s two-year withdrawal process from the EU.

During the event, the Conservative MP Ms Morgan also warned that the idea of a “no deal” – a threat to the EU nations proposed by Ms May during her keynote Lancaster House speech on Brexit – would be the “worst of all worlds” and “should not be entertained”.

In their “Brexit contract” foreword, the MPs add: “Vote Leave and the Government have made specific promises: leaving is a cost-free option; trade will be enhanced not hampered; there will be major savings from the EU budget; core arrangements with the EU, for example over national security, will remain unchanged; and the integrity of the United Kingdom will be protected.

"Now that Article 50 is being triggered, people will expect these promises to be delivered: this is the Government's Brexit contract with the British people.