Nick Clegg's Liberal Democrats were sucked deeper into the controversy over News Corp's planned takeover of BSkyB on Saturday as evidence submitted to the Leveson inquiry revealed close party ties with Murdoch executives.

In an email submitted to the inquiry by Fred Michel, the man who is now News Corp's chief lobbyist claims he attended a fundraising ball for Clegg's leadership campaign in 2007.

The Observer understands that Michel was referring to a Lib Dem champagne ball at the Park Lane hotel in September 2007. A spokesman for Clegg said Michel, who was not employed by News Corp at the time, had not given any money to the Clegg campaign and insisted that there had only been one fundraising event for Clegg's leadership, at someone's home.

However, the email on 3 November 2010 suggests that Michel, who has played tennis with Clegg and lives near him in Putney, had been linked into the Lib Dems for several years and was close enough to them to be on guest lists.

In the email, seeking a meeting with Danny Alexander, the Lib Dem chief secretary to the Treasury, Michel wrote to the minister's adviser Julia Goldsworthy: "Dear Julia, I hope you're well. We met at a fundraising dinner for the Lib Dem leadership election with Ian Wright."

Wright, a senior executive at the drinks firm Diageo, bankrolled Clegg's successful campaign and even deposited directly into the now deputy prime minister's personal account.

The lavish event was staged a month before the then leader Menzies Campbell resigned – although it was a period in which the leadership of the party was being openly talked about and Clegg was being punted as a likely successor.

Clegg has repeatedly claimed that – unlike the Tories and Labour – his party has remained at arms length from News Corp and its executives. At prime minister's questions in April, when David Cameron told the Commons that "hand on heart, we all did a bit too much cosying up to Rupert Murdoch", the deputy prime minister, who was sitting next to him, was seen to mouth: 'No we didn't'."

Other evidence submitted by Michel seems to call that into doubt. Text messages between Clegg's chief spin doctor Lena Pietsch and Michel, handed over to Leveson, show Pietsch in close contact with Michel in late 2010 and early 2011 when he was heading the News Corp lobbying operation in support of the BSkyB bid.

In January 2011, shortly after the Lib Dem business secretary Vince Cable had been removed from responsibility for the bid and replaced by culture secretary Jeremy Hunt, Pietsch entertained Michel in Downing Street. Michel texted back to Pietsch saying: "Thank you for such a nice catch-up by the Rose Garden. We should do it more often."

During his evidence to Leveson, Michel suggested that members of Clegg's staff had been helpful and reassuring when Cable – known to have reservations – was in charge of scrutinising the bid.

According to Michel's emails, Tim Colbourne, a Clegg aide, advised the News Corp lobbyist that he should try to get Labour to support the bid as this would convince Cable to back it.

Questioned over whether this conversation had really occurred, Michel added: "Well, if I put it in the memo, it's because it was discussed at the meeting. I understand that from a Liberal Democrat adviser it might not be comfortable to be reminded that it was discussed, but we definitely discussed this."

Michel added that Colbourne had also agreed that Clegg's office would "insist on the need for Vince to meet with us once Ofcom's report published." Michel told the inquiry: "I think we had an agreement that that was a good idea. That's what I remember."

In his evidence to the Leveson Inquiry, Colbourne said he did not agree with Michel's account of the meeting. In his written evidence Colbourne said:

"I do not recognise Frederic Michel's own account of this meeting as set out in his email to James Murdoch. I have no recollection of an 'honest discussion on the importance for us of getting Labour on board', and I completely reject the suggestion that I offered to 'insist on the need for Vince to meet with us once [the] Ofcom report [was] published'. I would not have offered to do so, and did not do so. When making handwritten notes of meetings, I always mark action points with an asterisk. There were no action points arising from this meeting."

According to a memo sent to Cameron by Hunt in March 2011, Clegg "reined in" the then energy secretary, Chris Huhne, who was "apoplectic" about the government's decision not to refer the BSkyB takeover to the Competition Commission and accept undertakings in lieu.

The memo, dated 17 March 2011, one of Hunt's fortnightly updates for the prime minister, said: "I did hear that Chris Huhne was apoplectic and advocated going to the media to criticise it – but partly because Don Foster was on-side Nick reined him in.

"The point to make to Nick (which I have also made to Chris) is that if I had referred it to the Competition Commission it would almost certainly have been judicially reviewed by News Corp as being unreasonable, given that Ofcom and the OFT had given it the all clear."

A Lib Dem spokesman insisted on Saturday that there was no evidence of Lib Dem ministers, advisers, or staff doing anything inappropriate at any stage. Earlier this month Clegg told Radio 4's The World at One: "The one thing I am very proud of as a Liberal Democrat leader both individually, personally, and as a party, is that we have never been in anybody's pockets.

"The idea that we could in any way be in the Murdochs' pocket – I mean, have you looked at the coverage in the Murdoch press about the Liberal Democrats over the last several years? It is just farcical."

• This article was amended on 21 July 2012 to include evidence given to the Leveson Inquiry by Liberal Democrat aide, Tim Colbourne.