The Ukrainian, the £136m flat – and the £60m redecoration

London's costliest penthouse has finally been sold. Trouble is, its new owner doesn't like the layout

The richest man in Ukraine has emerged as the buyer of Britain's most expensive flat – a penthouse apartment in the luxury One Hyde Park property development – for £136m.

Rinat Akhmetov, who is worth around £10bn, paid the sum for two apartments at the top of the new property, which he will knock through to make a three-storey penthouse pad.

The flats were sold unfurnished, and it is believed the Ukrainian oligarch will spend another £60m on renovations and interior design. A spokeswoman for Mr Akhmetov confirmed his holding company, System Capital Management, had invested in the property.

Mr Akhmetov may not be a household name here, but in Ukraine he is one of the biggest financial and political players. He is a staunch supporter of President Viktor Yanukovich and the most successful businessman to have emerged from the chaos of the post-Soviet grab for wealth. Even as the country's finances go from bad to worse, and millions of Ukrainians live life on the poverty line, Mr Akhmetov's fortune continues to rise. In the most recent list of billionaires compiled by Forbes magazine, he was rated as the 39th richest person in the world – above financier George Soros, Facebook founder Mark Zuckerberg and the Russian tycoon Roman Abramovich.

The Ukrainian had a very good 2010, with Forbes estimating his wealth increased by a staggering £6.6bn over the course of the year.

Mr Akhmetov has everything one might expect from an eastern European oligarch – a sprawling network of companies bought up from the state after the fall of the Soviet Union, a team of crack lawyers to counter any allegations of murky dealings, a charitable foundation, and of course a football club, Shakhtar Donetsk.

The only thing missing from his resume was an overblown pad in London, and the purchase of the One Hyde Park penthouse should more than make amends for that.

The development, masterminded by the Candy brothers, is believed to be the most expensive residential property in the world. Despite scepticism during the financial downturn, 45 of the property's 80 apartments have now been sold, as analysts say the very top end of the market is booming again – boosted in part by wealthy buyers from eastern Europe and the Middle East. The building has a cinema, swimming pool and wine cellar.

Mr Akhmetov's penthouse purchase is by far the most expensive, but even the cheapest one-bedroom flat in the property is believed to cost around £6.75m, while larger flats go for around £30m. Mr Akhmetov, the 44-year-old son of a coal miner, started out trading coal, and grew his business into a vast conglomerate with interests in metals and mining that employs 130,000 people.

The headquarters are still based in Donetsk, the gritty eastern Ukrainian mining town where he was born. He is an associate and a strong financial backer of President Yanukovich, who also began his political career in Donetsk, and is now an MP in the President's political party. He has faced repeated accusations in the past from Ukrainian journalists and also from prosecutors of ties to organised crime, but has always vigorously denied the allegations.

He has worked hard to counter the bad publicity by becoming one of Europe's most prolific philanthropists, forming a foundation to help socially disadvantaged Ukrainians.

Perhaps the most cherished arm of his business empire is the football club Shakhtar Donetsk, the team from his home town that he has turned into a major force in European football over the past few seasons.

In 2009, the team moved into a stunning new 50,000-seat stadium, financed by Mr Akhmetov at a cost of around £250m, which will be one of the host stadiums for the Euro 2012 tournament. In the same year, his side won the Uefa Cup.

They have eight Brazilians in the squad, and this season, made it to the quarter finals of the Champions League, only going out after losing to Barcelona.

Mr Akhmetov said after the loss earlier this month that he would "work 24 hours a day" to ensure that Shakhtar win the tournament in the near future.

The identity of many buyers of flats at One Hyde Park has been kept secret, but Mr Akhmetov's neighbours may include Vladimir Kim, a copper billionaire from Kazakhstan, assorted politicians and royals from the Middle East and 36-year-old Christian Candy, who along with his brother Nicholas was the developer of the project.

For many tenants, security will be an issue, and as such the windows are of bulletproof glass, the property is guarded round the clock, and the lifts are fitted with iris-recognition technology.