The former wife of an oil and gas trader has been awarded £453m in one of the largest divorce settlements ever agreed by a UK court. It confirms London’s status as the favoured location to bring divorce claims against super-rich spouses.

The couple in the case were not identified by the family court judge, Mr Justice Haddon-Cave, but the man, 61, is originally from the Caucasus, while the woman, 44, was born in eastern Europe.

Both were raised in Russia and met in Moscow in 1989, when she was studying in the city. He had been married before. The couple moved to London in 1993 and have two children. They both have accused each other of having affairs. The woman insisted their relationship had continued after her affair and only ended in 2013.

In his judgment, Haddon-Cave found there was a “subsisting marriage”, because the couple continued to holiday together and sleep together, and the woman was provided “with the unrestricted use of two of his credit cards and, latterly, the use of his yacht, plane and helicopter”.

The judge noted: “In 2013, for example, [the man] purchased jewellery for her worth €400,000.”

The yacht, helicopter and plane were bought in the man’s name in 2014 and then transferred to offshore companies, the judge said. During the hearings, the man gave evidence to the court via video-link from the yacht, which cost €260m and underwent a €42m refit in 2016.

The judgment read: “She said that marriages can survive affairs, and this marriage was one of them. She said [the man] had had numerous affairs himself during the marriage and had a child by another woman in 2013.”

The woman said she needed £39.27m to purchase a home in England as a result of the divorce, as well as £27.89m to buy a property abroad. She also needed £5.36m a year to live on.

The man was non-resident in the UK for tax purposes, which meant he could only spend 90 days a year in Britain. The family often enjoyed holidays at their house in France, at ski resorts and in the Maldives.

The judge noted: “They slept in the same bed when they were together, had sex, went on holiday regularly together with the boys, and shared a joint bank account.”

The woman produced evidence to show that the relationship continued after her affair, providing photographs of the couple with their sons and at a “lavish 50th birthday party in 2005, with [the woman] giving a speech for him”. She also produced a photograph of the couple “in an intimate embrace in the Maldives in 2013”.

She provided “documentary evidence, including emails with architects and contractors, showing that she was actively involved in the renovation of the holiday property in France, and planning their ‘dream home’ in the Caucasus”.

The woman was also involved in purchasing works for their art collection, which was valued at $112m. The judge noted that the man referred to her as “my wife” in emails to “organisers of an art fair, his solicitors, Amex, Sotheby’s and [the estate agent] Knight Frank”.

Concluding his judgment, Haddon-Cave said the couple had marital assets worth £1bn. Their wealth, he added, had been built up over the course of the marriage through “equal contributions to the welfare of the family, and should be subject to the sharing principle”.

A split approaching 50:50 was therefore appropriate. The woman had originally sought £350m, but because the two parties had not agreed a settlement she claimed a further £93m, comprising chattels at their English home valued at £2.5m an Aston Martin car in Surrey valued at £350,000, and the modern art collection valued at $112m.

Haddon-Cave said: “The total value of her claim is now, therefore, £453,576,152. This comprises some 41.5% of the total marital assets. I find that this figure is justified in all the circumstances.”

Commenting on the high settlement figure, Rosie Schumm, a partner in the family team at the law firm Forsters, said: “This big-money divorce settlement represents yet another example of the English courts’ unparalleled generosity towards the financially weaker spouse. This generosity is rooted in the fundamental principle that breadwinners’ and homemakers’ respective contributions to a marriage are of equal importance. With this in mind, London remains seen as the divorce capital of the world.

“Whether or not this settlement was indeed the biggest ever, as has been reported, is impossible to say. This is partly because an increasing number of high-net-worth couples are electing for private divorce and arbitration, where the proceedings and the details of the final settlement are kept entirely confidential.”

Deborah Jeff, head of family law at the London solicitor firm Seddons, said: “This was a long marriage of 20 years, meaning the starting point for a settlement is equal sharing of assets ... Today’s judgment reinforces that, as ever, London remains the place to divorce for the less-wealthy spouse, where their perhaps non-financial contribution is rewarded with the biggest dividend.”

The former Liberal Democrat MP John Hemming, who has campaigned for greater transparency in family justice, said the secrecy around the case undermined “the fundamental underlying principle” of open justice in British courts.

He said: “Here we have a case involving a foreign billionaire which has been heard in a family court in London entirely behind closed doors ... Yet the British taxpayer pays the judge’s wages and the wages of the court staff. They pay for every glass of water poured and every light switched on. Surely members of the public have a right to know something ... This isn’t open justice, it isn’t a transparent process and it isn’t right.”