It was the star lot at an auction held on Tuesday night at the Conservative party’s annual winter ball: a tennis game with Boris Johnson. The winning bidder? A Moscow-connected financier who is already the biggest female political donor in UK history.

According to media reports, Lubov Chernukhin paid £45,000 for the match with the prime minister and the Tories’ co-chairman Ben Elliott. In 2014 Chernukhin stumped up £160,000 to play tennis with Johnson, who was then London’s mayor, and the then prime minister, David Cameron.

This week’s donation is on top of £200,000 given by Chernukhin to the Conservatives in the run-up to the general election, according to Electoral Commission filings made public on Thursday. At the winter ball she shared a table with the education secretary, Gavin Williamson. She has previously had dinner with him in the Churchill war rooms – another fundraising auction lot, which cost her £35,000.

David Cameron and Boris Johnson playing tennis in 2011. Three years later Chernukhin paid £160,000 for a match with the pair. Photograph: Sean Dempsey/PA

Chernukhin’s gifts are perfectly legal: she is now a British citizen. The former banker, who has worked for firms such as ABN Amro, is the wife of Vladimir Putin’s former deputy finance minister Vladimir Chernukhin.

Meanwhile, the Russia report by parliament’s intelligence and security committee, which is said to explore Kremlin influence on British politics, has not yet been published, its release having been prevented by Downing Street before December’s general election.

Chernukhin’s latest £45,000 donation means the 46-year-old has given more than £1.6m to the Conservative party in 48 cash donations over the past seven years. For all this largesse, she avoids publicity and gives no interviews – in marked contrast to the party’s other generous donor with Russian connections, Alexander Termerko – never explaining why she chooses to give so much and so noticeably.

Her donations seem directed at whoever is the leader of the Conservative party at the time: last April she gave £135,000 for a dinner at the luxury Goring hotel with Theresa May and several female cabinet members.

The night out was captured in a photo by the then chief secretary to the Treasury, Liz Truss. (Chernukhin is pictured fourth right, next to May.) Downing Street at the time was irritated that Truss’s breezy post revealed the reality of how the Conservative party raises money.

At last year’s Black and White Conservative fundraising ball, Chernukhin won two more auctions, offering to pay £20,000 to dine with the then Scottish Tory leader, Ruth Davidson, and £30,000 for the Williamson dinner.

The bulk of the money Chernukhin willingly provides goes to the central coffers, although she made three donations totalling £14,500 for Brandon Lewis this year when the influential Tory, who is now Northern Ireland secretary, was the party’s chairman.

Records show she made three donations to the Conservative party in Witney, Oxfordshire, two of which date back to 2015, totalling £4,220 at a time when Cameron was the constituency MP.

Conservative sources indicate the party took advice in 2012 about Chernukhin’s donations. She was initially ruled an “impermissible donor” by the Electoral Commission, apparently because she was not on the electoral roll. An adviser to a senior May-era minister said the party was subsequently “advised there was no reason not to accept the money. And if somebody is good for £1 then they are good for much more.”

Born Lubov Golubeva, the woman who describes herself in Companies House filings as a banker and consultant was educated partly on the east coast of the US and came to the UK in around 2003. A few years later she met Vladimir Chernukhin after he left his native Russia, having apparently fallen out with Putin.

Vladimir had been appointed Russia’s deputy finance minister in 2000, aged 32, and two years later made chairman of Vnesheconombank (VEB), a bank and state corporation with reported close ties to the Kremlin security establishment.

In that position he had “regular meetings” with Putin, according to a judgment in a recent British court case. But his career was abruptly cut short when he was sacked in 2004, apparently because he was too closely connected to Mikhail Kasyanov, who had been ousted as Russian prime minister a year earlier.

Vladimir came to Britain, becoming a citizen in 2011, and seems to have had no shortage of money. Documents from the same court case indicate he wanted to sign a pre-nuptial agreement with Lubov.

Friends say he is a property investor, although not all deals have gone well: having purchased the old Midland Bank headquarters in the City of London for £72m in 2006, after the financial crash administrators had to sell it in 2009 when the buyer’s company defaulted on a loan.

Nevertheless, records show the couple live in an £8m mansion, owned by an offshore trust, overlooking Regent’s Park, and they have been eager to live the luxury lifestyle. After marrying in 2007 they tried to buy a second private jet for around £23m while at the same time acquiring two superyachts.

This year the couple were embroiled in an extraordinary British court case, fighting the Russian oligarch Oleg Deripaska over the particulars of the ownership of a lucrative property in central Moscow. The judge found Vladimir Chernukhin was a legitimate investor in the 9-hectare (22-acre) site with Deripaska in 2002, although he had made a “discreet” investment via an intermediary – his then girlfriend – given he was a minister and bank chairman at the same time.

The bitter $95m dispute was fought “aggressively on all sides”, Mr Justice Teare observed drily, with dozens of lawyers representing all the parties in court. In a detailed 96-page judgment, Teare was highly critical of the many players in the case for what he described as their lack of reliability in the courtroom.

They included Lubov Chernukhin, whose evidence, like that of many others in the case, was of varying quality, the judge said. She had “demonstrated a keen understanding of what documents said or did not say” and appeared to have “gained the impression that she had prepared well for the trial”, Teare said. But he also suggested she was “not being frank with the court” when it came to recollection of events that would have financially impacted on her husband.

Judging her one of several partial witnesses, the judge concluded: “Great caution is required before accepting her evidence” – although he ended up ruling in her husband’s favour.