The pair had been called back to testify to the Digital, Culture and Media Select Committee at Portcullis House in Westminster a week after the former CEO of Cambridge Analytica, Alexander Nix, had been given a grilling about his alleged involvement in the Brexit referendum of June 2016.
At the hearing on Tuesday, June 12, Mr. Wigmore denied they had received any money from the Russian government.
Mr. Banks and Mr. Wigmore both said they were concerned that evidence from the fake news inquiry was being used to bolster the campaign for a second referendum on membership of the European Union.
But the committee's chairman, Conservative MP Damian Collins, denied they were in cahoots with remainers or the organizers of that campaign.
The Sunday Times and The Observer both published articles on Sunday, June 10, claiming Mr. Banks had meetings with Russian embassy officials prior to the June 2016 referendum.
Mr. Banks, who put his own money into the Leave.EU organization, has repeatedly denied receiving any money from the Russian government.
'Political Witch-Hunt'
But Mr. Banks explained that was because the book was finished before one of the meetings with the Russian ambassador.
"If I wanted to hide it why would I mention it in the book? If I was intend on hiding my involvement with Russia I did a pretty bad job," Mr. Banks told the hearing.
He also produced a copy of his office calendar which showed no sign of him being in Russia in February 2016, as was claimed by the Sunday Times.
The Sunday Times claimed there were several meetings between the leaders of Leave.EU and high-ranking Russian officials between November 2015 and 2017.
Mr. Banks Ruled Out Investing in Russian Goldmines
One Russian businessman, introduced by the Russian ambassador the day after Leave.EU launched its campaign, reportedly offered Mr. Banks a deal to buy a goldmine in Russia, claimed the paper.
"I have no business interests in Russia and I have not done business in Russia," Mr. Banks told the hearing.
Mr. Banks said he discussed the proposal with Lord Guthrie, an expert on Russia, who told him to "be very careful dealing with Russia" and then with a London gold expert, Peter Hambro, who also advised him against pursuing the opportunity.
Mr. Banks and Mr. Wigmore explained that on one occasion in late 2016 they had met the Russian ambassador in London because the pair had links with Donald Trump's transition team and they were able to pass on a number to the Russians.
"I'm not an evil genius with a white cat controlling… western democracy," said Mr. Banks at one point, an allusion to a villain from a James Bond film.
"The Russian ambassador did not expect Trump to win and he was shocked. He said do you have a number and I did, so I passed it on (because the transition team had wanted me to) and he said 'thankyou very much'. Nobody thought Trump would win," Mr. Wigmore said, who said few governments had many any contact with the Trump team prior to the election in November 2016.
Mr. Wigmore offered to let the committee have copies of all the emails between himself, the Trump team and the Russian government.
'We Had A Nice Lunch And Got Trolleyed'
"We have done nothing sinister. We had a very nice lunch. The ambassador's wife cooked for us and the food was very nice….we got trolleyed (drunk), it was brilliant," said Mr. Wigmore.
"I was fascinated with that era…I'm writing a book about my dad's experiences. My father invited the Soviets to the Queen's birthday parade in Berlin for the first time….and the ambassador was very interested," said Mr. Wigmore.
Mr. Banks said the Leave campaign had been outspent two-to-one by the Remain side during the referendum but he said people voted for Brexit because their message, especially about "open doors" immigration resonated more with the British people than the economy-dominated "project fear" masterminded by George Osborne and others.
Mr. Banks asked the committee why they were only calling people from the Leave side to give evidence.
The committee continues to investigate data sharing and misuse around Facebook, Cambridge Analytica and other connected companies, as part of its wider inquiry into Fake News.
Whistleblowers' Credibility 'Shot To Pieces'
Mr. Banks said the allegations about himself and about Cambridge Analytica were largely the result of evidence from two people, Christopher Wylie and Brittany Kaiser, who he said were not "honest whistleblowers" and he added the credibility of both was "shot to pieces".
MPs asked the pair about the relationship between Leave.EU and Cambridge Analytica, as well as whether data from Leave.EU was used by companies such as GoSkippy Insurance and Eldon Insurance, which was owned by Mr. Banks.
The hearing was largely good-natured but Mr. Banks and Mr. Wigmore left abruptly at 1.40pm after being repeatedly asked to stay for "five minutes" to add a few further questions by Mr. Collins.
Mr. Banks insisted they had a lunch appointment which they were late for and had already stayed for far longer than they had been originally told it would take.