When ITV announced it would host an EU referendum show involving David Cameron and Nigel Farage on Wednesday night, the broadcaster probably didn't expect to be threatened. But then a late-night email arrived from the official anti-EU campaign, questioning its star reporter's neutrality and warning of legal challenges and "consequences for its future".
Vote Leave, which was designated as the official anti-EU campaign and believes Nigel Farage puts off swing voters, was furious to find the UKIP leader had been given the gig, rather than its own choice of Michael Gove or Boris Johnson, and immediately threatened legal action.
But now the campaign is worried that a rushed and furious late-night reaction after being caught off-guard looks less impressive in the cold light of the morning, with some of its own supportive MPs suggesting a potentially valid point has been obscured by a response that went too far.
Vote Leave sources told BuzzFeed News they had been due to meet ITV on Thursday to finalise the details of who would appear on the Q&A show, one of several debates and quasi-debates broadcasters are organising in the run-up to the referendum. As a result Vote Leave insist they were completely blindsided by ITV's announcement at 10pm on Wednesday that it had circumvented Vote Leave and had already reached agreement directly with Downing Street and UKIP.
No. 10 has made clear throughout that Cameron would not take part in a debate against any of his pro-Brexit Conservative colleagues, to avoid it becoming a "blue on blue" battle.
Vote Leave's team claim the first they knew about the deal was when they saw tweets of the Daily Telegraph front page. Then, just before the official ITV press release was issued at 10pm, they claim, the broadcaster rang to confirm they'd been cut out of the deal.
This left Vote Leave without a clear plan of how to react. Within minutes of the announcement they were briefing journalists who had been on the group's campaign tour of southwest England that they would pursue legal action against ITV for selecting an anti-EU speaker who they do not endorse.
Vote Leave "outraged" that ITV have announced Nigel Farage in their EU debate despite him not being the choice of official anti-EU campaign.
"ITV have effectively become part of the In campaign, we will take them to court and we will win," says a Vote Leave source. Who is unhappy.
With journalists' stories already rewritten to reflect Vote Leave's anger, it could have been left at that. Then an additional – and unsolicited – email arrived in inboxes at 11:16pm, attributed to a "Vote Leave source", threatening ITV and attacking its political editor, Robert Peston.
'The Establishment has tried everything from spending taxpayers money on pro-EU propaganda to funding the IN campaign via Goldman Sachs. The polls have stayed fifty fifty. They're now fixing the debates to shut out the official campaign. ITV is led by people like Robert Peston who campaigned for Britain to join the euro. ITV has lied to us in private while secretly stitching up a deal with Cameron to stop Boris Johnson or Michael Gove debating the issues properly. ITV has effectively joined the official IN campaign and there will be consequences for its future - the people in No10 won't be there for long."
Peston was less than impressed, while other news outlets turned on Vote Leave.
This cannot be real. It must be a practical joke. Ha ha ha https://t.co/nfIWz4Cqk4
Even some of the campaign's own pro-Brexit MPs were concerned the late-night briefing had undermined a potentially valid point about Farage's selection.
"The tone and content of the letter was OTT," Braintree Tory MP James Cleverly told BuzzFeed News. "But I understand why they were unhappy. They are the officially designated campaign and as such should get to say who speaks officially on behalf of the Leave campaign.
"Labour and the Conservatives would be furious if an election TV debate had someone speaking 'on behalf' of the party who wasn't either a member of that party or agreed to by party leadership. Farage isn't part of Vote Leave and is therefore no more legitimate a spokesperson than anyone else."
But Vote Leave did not leave the matter at that. Campaign spokesperson Rob Oxley went on BBC Radio 4's Today programme and said it was "blatantly obvious" there would be consequences for ITV for allowing Cameron to pick his opponent for the debate.
By this point the old divisions of rival anti-EU campaigns became more apparent, with Farage's spokesperson attacking Vote Leave for trying to keep him off what will be "undoubtedly be the defining moment of the referendum campaign".
They added: "It is deeply disappointing that rather than rallying behind Nigel Farage for what will be the biggest one-on-one debate of the referendum campaign, Vote Leave are instead threatening court action to stop Nigel from taking on the prime minister."
In summary: anti-EU UKIP are at war with anti-EU Vote Leave after Vote Leave attacked ITV/Peston for being pro-EU by putting Farage on TV.
A more sober Vote Leave statement, officially attributed to a campaign spokesperson, arrived in journalists' inboxes shortly after 9am this morning but it was too late to undo the damage caused by last night.
Although there is still a so-called "3 vs 3" debate planned for ITV News in which Vote Leave expect to be involved, they fear that the government is now close to successfully having its preferred choice of opposition for the channel's biggest event. Downing Street is unsurprisingly delighted.