Vote Leave, the official Leave campaign in the Brexit referendum, has attacked the Electoral Commission for making "false accusations" about the campaign – blasting the watchdog's report for peddling conspiracy theories.
The Brexit campaign, which was backed by Cabinet ministers Boris Johnson and Michael Gove, has been investigated by the watchdog three times over whether it breached spending limits during the EU referendum.
The team has always denied wrongdoing – something the Electoral Commission (EC) initially accepted. But the case was reopened shortly after a group of campaigning lawyers started legal action claiming the watchdog was not doing its job properly.
Ahead of the publication of the EC's final report, Vote Leave has delivered the watchdog a dossier, claiming to rebut in detail all of the charges.
Among its arguments are the fact that no senior Vote Leave staff member has been interviewed at any point in the last two years.
"This is a clear violation of the EC’s duty to act fairly and sadly ensures that its third inquiry will fail to persuade anybody that these issues have been properly resolved," a Vote Leave source said. "Whatever one’s view of the referendum, it is astonishing that the EC could spend two years holding three inquiries and never even have a single conversation with a single one of the Vote Leave staff responsible for the matters under investigation."
As a result the allegations "do not stand up to scrutiny and will be dismissed in court", they added.
"Their failure to seek or engage with this evidence suggests that this public body is highly partial and is following a deeply political agenda," Vote Leave claims. "Their failure to follow due process and the principles of natural justice means that Vote Leave are very confident that it will overturn these findings when it appeals."
Specific claims that are rebutted include an alleged conspiracy between former campaign director Dominic Cummings and donors to raise money for grassroots group BeLeave, for use with data company CHECK AIQ – a coordinated action which would go against rules.
Vote Leave claims there is evidence that disproves this and "this central allegation could have been easily dismissed had the EC actually interviewed Mr Cummings to establish some basic facts".
It also rebuts the claim that BeLeave was established in May 2016, and was not in control of its own messaging, citing "dozens of pages of evidence in the EC's own report" that proves this was not the case.
The dossier also addresses claims made in The Observer and Channel 4 that Vote Leave used data harvested from Facebook by Cambridge Analytica. Although the EC's report "ignored this original conspiracy", Vote Leave claims the EC "is now spreading a further conspiracy theory about BeLeave without evidence".
It also notes that no investigation has been carried out into the coordination of Remain campaigns, despite apparent admissions of such activity by David Cameron's former spinner Sir Craig Oliver.
"This is in line with the EC’s behaviour during the referendum," Vote Leave said. "The EC over and over again helped the Remain campaign and tried to undermine Vote Leave. This latest report is in line with its conduct in the referendum. Given its chairman [Sir John Holmes] has attacked Leave’s victory, and other EC staff do not even try to pretend to be politically impartial, this latest report spreading conspiracy theories is sadly no surprise."
The Electoral Commission said: "The Commission will give due consideration to the representations made to the Commission, including those made by other campaigners under investigation. We will then, at the earliest opportunity, publish a thorough and detailed closing report in order to provide a full and balanced account to the public and to parliament."