Ally turned critic of Russian president is believed to be London and is accused of siphoning money from bank for personal use

An exiled Russian oligarch who was once so close to the Kremlin he was known as “Putin’s banker” has been put on the Interpol wanted list by Moscow after falling out with his former associates.

Sergei Pugachev – whose riches Forbes magazine estimated at more than $2bn (£1.3bn) at the peak of his wealth – fled Russia after claiming hostile interests were trying to seize his businesses. In recent weeks he has given interviews critical of President Vladimir Putin and the Russian political system. He is believed to be living in London.

In July, Pugachev had his assets frozen by a court in London as part of a dispute with a Russian liquidator, and was given a spending limit of £10,000 a week.

He was an associate of the former president Boris Yeltsin, and later became close to Putin, with a portfolio of interests across construction, banking and shipbuilding. He was also a senator, but his fortunes changed in 2010 when his bank defaulted on its debts and lost its licence.

Russian prosecutors accuse him of siphoning money from the bank for personal use. Pugachev denies the allegation, and says the charges against him were an excuse to seize his assets. “Today in Russia there is no private property. There are only serfs who belong to Putin,” he told the Financial Times last month.

Vladimir Putin and Sergei Pugachev in 2000. Photograph: Reuters

In an interview with Time magazine, he said: “If Putin says he wants to buy something, you cannot say you do not want to sell. If he says, ‘I want to buy something,’ then you say, ‘Thanks for saying you want to buy it, and not just taking it.’”

This month, Pugachev’s lawyers told the high court in London that he was worth “no more than $70m” after his assets were frozen.

The notice on Interpol’s website says Pugachev is wanted by Russian authorities for misappropriation or embezzlement. But the UK authorities are unlikely to act on the Interpol request or on any extradition request from Russia. British courts have previously turned down such requests , suggesting they are often politically motivated.

Russia repeatedly tried in vain to have Putin’s original political backer turned arch-enemy, Boris Berezovsky, extradited from London. Berezovsky was found hanged at his Surrey estate last year. It also lost a battle to extradite Yevgeny Chichvarkin, a mobile phone magnate who fled the country after he said corrupt officials seized his business. Chichvarkin now runs a luxury wine shop in Mayfair.

Pugachev was very close to power in Russia, and until recently he remained an elusive, media-shy figure. He was known for his Orthodox Christian views and his relationship with Alexandra Tolstoy, a former BBC presenter and descendant of the novelist. The pair met when Pugachev was still married to his first wife and Tolstoy was married to a Cossack horse trainer, who has since attempted to sue her for trying to evict him from their Moscow flat.

But since Pugachev’s fall from grace, he has become an outspoken critic of the Kremlin and Putin, speaking in scathing terms about the Russian president’s intellectual capacity and grasp of economics.

“Vladimir Putin does not understand economics. He does not like it. It is dry. It’s boring to hear these reports, to read them. He likes clear things: Russia’s moving ahead; how great everything is. He does not have a deep understanding of what is happening,” Pugachev told Time. “Putin’s close circle understands he likes good news, so they always bring him good news. Whatever is happening, it’s good. For him, it’s enough to be in a good mood.”

Pugachev knew Putin from the Russian leader’s first days in the capital, after he was taken to Moscow from his home town of St Petersburg in 1996 to work in the presidential administration. Pugachev recalled a nondescript bureaucrat who gave little clue that he would rise to become Russia’s leader for the foreseeable future.

“He’d always have well-sharpened pencils, a clean sheet of paper and a newspaper,” Pugachev remembered. “There were no documents, nothing. I had been in politics about 10 years and seen everyone. They’d have tons of documents. They’d always be doing something. But with him it was just quiet, no one there, no meetings, everything quiet. He’d sit there, or watch TV. He really likes watching TV.”