ITV has withdrawn plans for a Brexit debate on Sunday night, meaning there is now little chance of a televised head-to-head encounter between Jeremy Corbyn and Theresa May before next week’s crucial vote.

In what might turn out to be one of the most pointless and tortuous stories of the Brexit process, the broadcaster abandoned its planned debate over the prime minister’s withdrawal deal despite two weeks of behind-the-scenes negotiations after Downing Street refused to sign up to its proposed head-to-head format.

Earlier this week the BBC announced it was pulling its rival bid to host the debate after becoming exasperated with Jeremy Corbyn’s team, who were not willing to allow representatives of minor parties and proponents of a second referendum to be included on a panel.

Both the Conservatives and Labour are blaming each other for the failure to agree on the ground rules. At one point the impasse meant that two rival debates were being planned by both ITV and BBC for the same time slot, with no idea whether either of the leaders would turn up. In the end all bids involving May and Corbyn collapsed.

Instead, Channel 4 will push ahead with its already announced plans to host “The Real Brexit Debate”, featuring other politicians.

The saga began almost two weeks ago when May challenged Corbyn to a head-to-head discussion on television. Perhaps unexpectedly, Labour swiftly agreed, prompting BBC, ITV, and Sky News to bid against each other for the right to host the debate.

Labour swiftly backed the ITV format, which would have been hosted by Julie Etchingham at 7pm on Sunday with no studio audience, instead focussing on the two leaders, which the party believed would allow Corbyn to criticise the prime minister on non-Brexit issues such as austerity. It would have supplanted a celebrity special edition of The Chase.

The Conservatives preferred the BBC bid, which would have replaced an episode of David Attenborough’s Dynasties series. It would have included a panel of eight politicians and experts representing smaller political parties and alternative views, allowing the BBC to meet its commitment to represent smaller voices. Downing Street felt this would play to its strengths, potentially by allowing it to make opposition to the deal look divided.

Instead, the real victims could be those who had been looking forward to seeing Home Alone on Channel 4 this Sunday evening. The classic Christmas movie will need to be shunted out of the way to make way for a debate at 7pm between “four high-profile politicians” representing “the main divisions in the House of Commons”. These will encompass a supporter of Theresa May’s deal, a supporter of a softer Brexit, a backer of a harder Brexit, and a supporter of a second referendum.

Sky News has previously said the chaos justified its demand for an independent debates commission to organise such programmes in the future.

A Labour spokesperson blamed Downing Street for the failure to agree a leaders’ debate: “Theresa May is once again running scared of debating Jeremy Corbyn, just as she did in the general election. Jeremy Corbyn accepted the prime minister’s offer of a debate on Brexit immediately. He said he would relish the opportunity to debate her, and that remains the case.

“Labour believed the head-to-head offer from ITV was the most straightforward format. A head-to-head would give viewers the greatest clarity and allow both speakers to get into detail.

“The prime minister has refused to join Jeremy in a head-to-head debate. Her team tried to confuse people with a convoluted format. But the British public will see this for what it is – Theresa May unable to face real scrutiny over her crumbling deal.”

One broadcasting source suggested Downing Street might have gone cold on the debate plan after the protracted public discussion over the format, which was being led by Number 10’s communications chief, Robbie Gibb.

The source suggested May and her chief of staff, Gavin Barwell, cooled on the idea as the House of Commons vote approached.