Britain may be on the verge of a “great betrayal” as MPs ramp up their efforts to prevent a hard Brexit, the outgoing UKIP leader Nigel Farage has warned.

Speaking on his weekend show on LBC radio, Farage highlighted recent interventions by politicians including Tony Blair and Peter Mandelson, claiming the “political establishment is ganging up together to betray Brexit voters”.

“Lord Mandelson, the cheerleader in chief, is trying to get us to stay in the single market,” Farage said.

Over the last few weeks, a political distinction has grown up between ‘soft’ Brexit, which means staying within the single market and accepting rules such as the free movement of people which accompany that, or ‘hard’ Brexit, which means leaving the single market and negotiating trade deals.

On Friday, former Prime Minister Tony Blair called for a second referendum on membership of the EU, saying: “If it becomes clear that this is either a deal that doesn’t make it worth our while leaving or alternatively, a deal that is going to be so serious in its implications, people may decide that they don’t want to go.”

The following day the Conservative MP Nadhim Zahawi said that Blair was “preposterous” to demand a re-run, saying: “The British people have spoken decisively and so loudly that not even ‘Remoaners’ with the hardest of hearing can pretend not to have heard them.”

But he then made the argument that Britain should hand over £8.5 billion a year to the EU to make up the budget shortfall caused by Brexit, adding: “The only issue to negotiate is how high our payment would be in return for single market access, and that must be left to our negotiators.”

Farage countered: “If we stay in the single market it would also mean some degree of free movement of people. So if you think about it, as far as I’m concerned, every single thing that we voted to get out of, in this referendum, we’re now being told, not just by Lord Mandelson, not just by people like Tony Blair, but Tory MPs like Nadhim Zahawi telling us we must stay part of this single market.”

He added: “I’m just beginning to wonder, and worry, are we on the edge, perhaps, of a great betrayal?

“Because whichever side you voted in that referendum – you know 17.4 million people voted for us to leave the EU – it was the biggest exercise in democracy ever in the history of this country.”

He drew support from his audience who called in to agree that the Brexit they voted for was being undermined. Diana, from Putney, told him: “There is a ridiculous argument that we know what we’re going to get if we stay in the EU. We don’t!

“And the bits we do know about are not what we want.”

Farage agreed, adding: “If Brexit doesn’t happen, there is going to be political anger that has never been seen in this country.”