Bob Dudley, the embattled chief executive of TNK-BP, the oil group, launched a vigorous fightback yesterday against the authorities who barred him from working in Russia.

Mr Dudley, who is running the company remotely while in hiding after being forced to flee Moscow on July 24 following the withdrawal of his work visa, accused Russia's State Labour Inspectorate of an abuse of power after Moscow's Presnensky court issued a two-year ban against him last week for alleged labour violations at TNK-BP.

Dudley drew unexpected support from Presnensky district prosecutors, who filed a protest against the ban, claiming legal procedures had been broken by the court, which is now obliged to review the ban.

In a formal complaint filed by Mr Dudley against the inspectorate dated August 19 and sent to five different branches of the Russian state, including the FSB - the successor to the KGB, Mr Dudley said that he had been a victim of an intense campaign of harassment by three named inspectors.

“The unambiguous conclusion is that [they] were carrying out somebody's orders and we request that this be investigated,” Mr Dudley wrote.

TNK-BP, Russia's third biggest crude producer, has been locked in a shareholder battle between its two 50 per cent co-owners: Britain's BP and AAR, a consortium of four Soviet- born billionaires.

He said that seven inspections at TNK-BP between June 6 and August 12 took place during an escalating “corporate conflict” between the two sides, indicating the existence of an ulterior motive.

The letter, which was sent to the head of the Labour Inspectorate, the chairman of the country's anti-corruption council, the head of the FSB and the general prosecutor, has emerged as investor confidence in Russia continued to evaporate.

Moscow's RTS index recorded its lowest weekly close yesterday since 2006. It has fallen more than 25 per cent since June 30, making it one of the world's worst performing markets.

The row over TNK-BP, a government attack on the steelmaker Mechel, falling oil prices and the invasion of Georgia have driven the RTS index down from 2,303 on June 30 to 1,707 last night.

Figures from Russia's central bank also indicated a sharp fall in its foreign currency reserves of $16.4billion for the week ended August 15 - one of the largest weekly drops in a decade.

Adding to the sense of alarm over events unfolding in Russia, AIM-listed Dragon Oil has said that its exports of crude from Turkmenistan could be disrupted by the invasion of Georgia.

Mr Dudley's letter included detailed complaints against three individuals at the labour inspectorate identified as S.E Pogorelov, M Yu Malyuga and N. V Volskaya, accusing them of a series of procedural errors and abuses. The inspectorate has rejected the claims.

It emerged last night that Moscow prosecutors had launched a protest against the court's ban on Mr Dudley, raising the prospect that it could be removed. TNK-BP is due to hold a board meeting on September 25 at which Mr Dudley's leadership of the firm will be discussed along with the possibility of an initial public offering.

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