Mr Hannan called on all Brexiteers to boycott a second Brexit poll if any MPs succeed in establishing a new referendum, insisting the British people have already decided on the UK’s fate.
He told Al Jazeera show UpFront: “A second referendum would be utterly illegitimate. I would not vote in it, because we’ve just had a referendum.
“When the British people have given a very clear mandate, and the unelected peers and the elites then turnaround and undo it, we should not play that game.”
His dire warning comes after former MI6 chief, Sir John Sawers, backed a second people’s vote.
Sir John Sawers, who was in charge of the Secret Intelligence Service from 2009-14, insisted Britain should support a second referendum to “heal” the country’s Brexit divide.
He said: “I believe that all of us, the advocates of Britain leaving the EU as well as those arguing we should still remain a member, should support a second referendum.
“A national decision by referendum would at least be final and would allow us to start healing the divisions that have opened up over the Brexit question.
“Only a second referendum will put the issue to rest.”
Sir John insisted Brexit could leave the UK “weak” and vulnerable, giving a rise to external attacks, such as the Russian novichok poisoning.
He warned how Moscow could easily “pick on Britain and bully us because we were looking weak”.
Sir John added: “The Americans to some extent are walking away from their relationship with Europe, and we are walking away from the relationship with the European Union. The west is fragmented”.
At least 670,000 people took to the streets of London today for the People’s Vote march, in the country’s biggest anti-Brexit protest since the referendum vote in 2016.
Several MPs gave speeches to crowds, declaring their support for a second vote if the motion was passed through Government.
Conservative MP Sarah Wollaston said the protest meant anti-Brexit campaigners can “no longer be ignored”, adding that the public “need to be given the chance to see” if a second referendum would result in a Leave majority.
The MP for Totnes, South Devon, said: “Let people weigh up the pros and cons of the actual deal or no deal that we’re heading for and then they can give their informed consent, and for me that’s the key principle here.”
In a video message of support, Nicola Sturgeon, the First Minister of Scotland, said: “Let me say this loudly and clearly, if the issue comes before the House of Commons, SNP MPs will support a People’s Vote which includes the option to remain in the EU.”