The UK government will face a Brexit backlash once the public realises it cannot deliver on its "outlandish" and "utopian" promises, Nick Clegg said on Tuesday (28 March).

The former deputy prime minister also claimed that he sees an "inner Remainer" within Theresa May despite her being poised to invoke Article 50 and trigger divorce talks with the EU on Wednesday.

"There is going to be a growing gap between what the public legitimately expects of Brexit and the reality that [they are] actually able to deliver," the Liberal Democrat MP told a press conference in London.

"In other words, we are now coming to an end of nine months of political debate in Westminster, which has been introverted, self-absorbed, the nation has been talking to itself – dare I say it, the Conservative Party especially talking to itself – distinguished by wishful thinking, utopianism and ever more outlandish promises being made to the British people."

Clegg pointed to Brexit Secretary David Davis' admission on BBC One's Question Time on Monday night to back this claim up. The senior Conservative said immigration levels should rise and fall to meet the demands of the UK labour market after Brexit.

Immigration was a major issue during the EU referendum, with lead campaign Vote Leave endorsing an Australian-style visa system. The Tories have also continuously promised to cut net migration down to "tens of thousands", with most recent figures sitting at more than 273,000 according to the Office for National Statistics.

Clegg was joined by Labour MP Chris Leslie and former Conservative Education Secretary Nicky Morgan at the Open Britain event. The cross-party group of MPs unveiled a "Brexit Contract" in a bid to hold the UK government over the two-year-long negotiating period with the EU.

Tens promises inside the 'Brexit Contract'

1. EU trade The 'exact same benefits' delivered as we currently have within the Single Market and Customs Union.

2. Trade deals. Lots of new trade deals with new countries that are ready to sign on the day of our departure from the EU.

3. Money. Savings from contributions invested in public services, including £350m a week for the NHS.

4. Northern Ireland. No changes to the border between Northern Ireland and the Republic.

5. Rights. Citizens', workers' and environmental rights currently guaranteed by membership of the EU to be fully protected.

6. Security A deal on security that maintains and enhances our cooperation with the EU.

7. United Kingdom. The integrity of the Union protected and made stronger.

8. Science. Science and research partnerships with the EU strengthened.

9. Date. The UK will be fully out, including required ratification, in 2019.

10. Immigration. A dramatic reduction in net migration while also keeping the UK open to the talent and skills that UK business need.