The party’s deputy chairwoman and Theresa May’s former chief of staff both acknowledged a crash-out is an option in little over a year’s time – even if the Tories win the general election and pass the Brexit deal.
Hours earlier, the prime minister had issued a video insisting he would not extend the brief post-Brexit transition period – during which the UK will abide by EU rules – beyond December 2020.
It means the UK would lose all economic and security ties with the EU unless a new complex deal can be struck in time – a prospect dismissed by trade experts as all-but impossible.
Asked if “no-deal is back on the table now”, Helen Whately, the deputy chairwoman, said: “There is always a case of what will happen if there is a walkaway.
“Of course there is always a question that you would walk away rather than have a bad deal.”
And Gavin Barwell, Ms May’s former key aide and now a Conservative peer, said: “It’s always been there until you get the whole thing finally solved – that’s always been the case.”
There are suspicions that a no-deal at the end of 2020 remains the aim of hardline Tory MPs, which arose when one said it was their reason for backing Mr Johnson’s deal.
Those hardliners, in the European Research Group, are reported to have held secret talks with Mr Farage that appeared to broker his dramatic Monday climbdown.
The timetable for a new trade deal is even shorter than the end of 2020, because an extension to the transition period must be requested by June 2020.
Incredibly, the non-binding political declaration agreed by the UK and EU says the future negotiations “will convene at a high level in June 2020” – the deadline for making that extension decision.
Brussels has already warned that the UK’s wish to diverge from standards - on workers rights and environmental and consumer protections – will put up big obstacles.
Keir Starmer, Labour’s Brexit spokesman, warned: “The Tories are now so obsessed with chasing the Brexit Party that they are prepared to implement a disastrous no deal at the end of next year.
“That would wreck the economy, put jobs at risk and damage communities across the country.”
In the interview, on the BBC’s Politics Live programme, Lord Barwell denied that what the Brexit Party leader called his “unilateral Leave alliance” with the Tories meant his party had “adopted Nigel Farage’s agenda”.
“Nigel Farage has backed down without the government shifting its position at all,” he insisted.
“There’s nothing in that video that is a change from what Boris Johnson has been saying.”
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies