Arron Banks (pictured with wife Catya) had three meetings with Russian ambassador Alexander Yakovenko

Explosive new claims of Russian meddling in the Brexit referendum emerged last night as it was revealed that the millionaire who bankrolled the Leave campaign had a series of secret meetings with Vladimir Putin's UK envoy.

Arron Banks had three meetings with Russian ambassador Alexander Yakovenko, fresh evidence shows, despite previously claiming to have had only a 'boozy lunch' with him.

Leaked emails written by Banks and his Leave.EU right-hand-man Andy Wigmore – both close friends of ex-Ukip leader Nigel Farage – allegedly show they were in close contact with Russian officials throughout the referendum campaign and afterwards.

Former Ukip donor Mr Banks is also said to have given Russian officials telephone numbers for members of Donald Trump's presidential transition team, just days after he and Mr Farage visited Trump Tower in the wake of the shock US election result.

The cache of messages will be considered by the Commons Digital, Culture, Media and Sport Select Committee, which is investigating Russia's attempts to subvert democracy with 'fake news'.

Mr Banks and Mr Wigmore last night set the stage for an electrifying hearing of the inquiry on Tuesday, vowing that they would give evidence to committee chairman Damian Collins about their emails being 'hacked'.

Mr Banks wrote on Twitter that the messages had been 'stolen' and added: 'At this rate I'll be attending @DamianCollins on Tuesday as planned!'.

He had previously vowed not to attend the hearing, branding the committee a 'partisan witch hunt' and accusing it of 'collusion' with pro-EU campaigners.

Mr Wigmore also tweeted Mr Collins yesterday: 'Fill your boots and all from #hacked emails, surely not legal? See you on Tuesday.' He tagged Mr Banks in the message.

Last night Mr Collins told The Mail on Sunday: 'The concern we have is there seems to be evidence of very close contact between Leave.EU and the Russian embassy during the referendum campaign, far greater than they have previously admitted to.

Banks and Nigel Farage meet President Donald Trump at the Trump Tower in NYC

'We will be questioning Mr Banks and Mr Wigmore about this.'

Tuesday's showdown will coincide with crucial votes in the Commons on Brexit. Theresa May will attempt to stop rebel Tory MPs defeating the Government by backing amendments that would keep Britain in the Single Market or a customs union with the EU.

The Government and the intelligence services are likely to face calls to investigate the new evidence of contact between the Brexiteers and Putin's officials.

Just last month MI5 chief Andrew Parker branded the Russian government the 'chief propagandist' in a campaign to undermine Western democracies.

Mr Banks, who is married to a Russian, has previously claimed his only contact with Russian officials came at a Ukip conference in 2015 when a man called 'Oleg' invited him to a private meeting with the ambassador.

'Our host wanted the inside track on the Brexit campaign and grilled us on the potential implications of an Out vote for Europe,' Mr Banks wrote in his book, Bad Boys Of Brexit.

He said 'diplomatic relations improved' when the Russians produced a bottle of vodka that had been 'made for Stalin personally'.

The new claims of closer contact between Mr Banks and Russia will raise fears among Leave backers that Brexit will be discredited in a welter of sleaze allegations.

Banks previously claimed to have had only a 'boozy lunch' with Russian Ambassador Alexander Yakovenko (pictured)

The Government and the intelligence services are likely to face calls to investigate the new evidence of contact between the Brexiteers and Putin's (pictured) officials

Last week MPs took the rare decision to vote to order Dominic Cummings – mastermind of the official Vote Leave campaign – to give evidence to the same committee over claims that he broke election spending rules.

Mr Cummings, former confidant of Cabinet Brexiteer Michael Gove, had said he would not attend. There have also been claims that Brexit campaigners misused personal data obtained via controversial firm Cambridge Analytica in order to target voters.

The Electoral Commission watchdog is already investigating whether or not Mr Banks breached finance rules over Brexit campaign donations.

His meetings with Moscow's man in London are not the only suggestion of a Russian link to Brexit.

This newspaper exposed last year how the pro-Brexit Legatum Institute helped Mr Gove and Boris Johnson press Mrs May for a 'hard Brexit'.

Secretive billionaire Christopher Chandler, who founded the think-tank, angrily denied any Russian link.

But last month he was accused in the Commons of being a suspected Russian agent with links to money-laundering. Mr Chandler was said to be an 'object of interest' to the French, who suspected him of 'working for Russian intelligence' – claims he strongly denied.

But his attempt to shrug off another Russian link was undermined when it emerged that his brother Richard Chandler's company, Clermont, said in a pamphlet that the brothers placed their own director on the board of Russian energy giant Gazprom, then teamed up with Putin to launch a management coup. Clermont has since withdrawn the statement and said it was only a shorthand description of events.

Fake news commissar blamed the UK for Skripal affair

By Jonathan Petre

Delivering his carefully crafted taunts with perfect manners and a chuckle, he is eerily reminiscent of a James Bond villain.

Russia’s ambassador to the UK, Alexander Yakovenko, has been a key part of the Kremlin’s disinformation campaign against Britain during the escalating war of words over the poisoning of Sergei and Yulia Skripal.

When Britain accused Russia of the attempted murder of former double agent Sergei and his daughter in Salisbury, he not only denied the claim but turned the tables by insinuating that British scientists could have been involved.

Russia’s ambassador to the UK, Alexander Yakovenko, has been a key part of the Kremlin’s campaign against Britain during the escalating war of words over the Skripal incident

The suave 63-year-old diplomat suggested it was ‘highly likely’ that British scientists had a supply of the military-grade poison Novichok at their nearby Porton Down chemical-warfare facility because they had identified the cause of the poisoning so quickly.

But MPs were unimpressed, accusing Mr Yakovenko of ‘doublespeak’ and comparing him to ‘Comical Ali’, the former Iraqi propaganda chief, when they questioned him later in front of the Russia all-party parliamentary group.

Suggesting that ‘UK security services’ were behind the incident in March, Mr Yakovenko said Russia had been blamed but British authorities admitted they had no suspects.

The UK saw Russia as ‘enemy number one’, he claimed, adding: ‘The people don’t buy this kind of policy.’

But Tory MP Bob Seely told him: ‘People treat you like they treated Comical Ali – someone who is great entertainment value who relies on conspiracy theories.’

The legally trained deputy minister in Russia’s Foreign Affairs department, who has been ambassador in the UK since 2011, has also suggested Yulia was being manipulated by the British authorities after her release from hospital. But she replied she did not wish ‘to avail myself’ of the services of the Russian embassy. Mr Yakovenko later suggested that Britain had kidnapped her and her father.

Among his other ‘fake news’ triumphs was his embassy’s message to Russian tourists visiting Britain to be aware that British agents may plant ‘foreign objects’ in their luggage.

Its embassy told visitors: ‘Given the Russophobia in British society artificially imposed by the authorities, it is necessary to avoid conflict situations with the local population.’

A Whitehall source said at the time: ‘We’re frankly astonished – it is pure fake news.’