Alexander Lebedev, the Russian billionaire, said on Friday that he would divest himself of his business holdings and devote his time to his newspapers, the Independent and London Evening Standard in Britain and Moscow’s Novaya Gazeta.

An outspoken critic of the Russian government, Mr Lebedev also made a separate announcement that has mystified Moscow political circles – he has decided to seek membership of a political bloc led by Vladimir Putin, Russia’s prime minister, aimed at competing in December parliamentary elections.

Mr Lebedev said this was not intended as a gesture of support for the authorities.

“They said that anybody can join and I’ve noticed that they said they will fight corruption. Since I think every other institution failed in this country, why not offer my good offices to them,” said Mr Lebedev.

His NGO, “Our Capital”, on Friday applied to join the Putin-led bloc known as the “All Russian National Front” which includes the ruling political party United Russia.

On his decision to divest, Mr Lebedev told the Financial Times in an interview that he felt being a billionaire was incompatible with his goal of championing investigative journalism and sapped his credibility as a serious critic of the status quo. “If I go and fight corruption, I should be taken off the Forbes list because who is going to believe me otherwise?

“I’ll do everything to cease being a shareholder in any of my businesses” he said, though he declined to be specific. Mr Lebedev said his decision was partly motivated by the frustration at the high levels of corruption in Russia.

The 44th richest man in Russia, with a fortune estimated at $2.1bn, according to Forbes Magazine, he owns London newspapers The Independent and the Evening Standard, in addition to holdings in agriculture, aircraft leasing, airlines, banking, real estate, and oil.

“In the present climate doing any business here [Russia] is completely beyond any rationale, you have to be insane really. There is not a sphere where the state wouldn’t push you out.”

A former KGB officer based in London, Mr Lebedev has gained the reputation of a gadfly and outspoken opponent of the government, owning opposition newspaper Novaya Gazeta which frequently published muckraking articles about corruption at the heart of the Russian state.

He said his newspapers, including Novaya Gazeta, would be the only interests he retains. “I will keep a hold of newspapers, and focus on newspapers and investigative journalism” he said. Mr Lebedev stopped short of giving any specifics, however, saying “I’ll explain everything in a couple of weeks.

“Some will be donated to charity, some things I’m not even sure what to do with” he said.

He stopped short of saying he would sell his 14 per cent stake in Aeroflot, Russia’s national air carrier, as well as his large stake in National Reserve bank “I have a way to settle it” he said.

“Selling everything in the market like that is not very plausible, is it? I mean who is going to buy anything now?”

Given his notoriously critical stance on the government, his decision to join the Putin-led National Front is somewhat mystifying to his associates. But Mr Lebedev said he intended to work from within the establishment to change it. “If they let me have a seat in the Duma [Russia’s lower house of parliament], I spend a few years a few years being in their fraction, always being against them, and pursuing my own agenda.

“Maybe Putin has a different agenda in his mind because he is the only one who can do something about corruption, he is running everything here and he is the one who really has all of the keys in his hands.”