Russia’s richest man, ex-Yukos CEO Mikhail Khodorkovsky, has pleaded not guilty to a raft of charges that could jail him for 10 years, while authorities tightened the grip on the beleaguered oil company’s key production assets.

Billionaire Chelsea boss Roman Abramovich may be the next target of Kremlin prosecutors after the remote region he runs was declared bankrupt by Russia’s highest audit body.

The jailing of Russia’s richest man in what is widely seen as a politically-driven attack on his oil empire could herald a return to Soviet-style repression that is bound to trigger capital flight, media and politicians warned today.