One of the biggest fraud trials in British history is set to begin in the High Court today amid fears that it could harm London's reputation as a forum for commercial disputes.

The case, which arose from a fight for control of an aluminium smelter in Tajikistan, one of central Asia's poorest countries, is expected to cost almost £90 million in legal fees. Only two commercial cases in the UK are believed to have cost more.

The dispute has already led to proceedings in several countries and has entangled two of the world's most powerful aluminium producers: Rusal, the Russian company controlled by Oleg Deripaska, and Norsk Hydro, the Norwegian industrial giant.

The final legal bill is likely to reignite debate over the cost of litigation in London at a time when hourly rates for the City's top lawyers have reached £750 — only slightly less than Tajikistan's annual GDP per capita.

The case centres on allegations of bribery and corruption made by Talco, a state-owned Tajik aluminium smelter, against its former business partner, Azar Nazarov, a Tajik businessman now based in the UK. The smelter is the third largest in the world and the country's most important industrial asset, accounting for more than half of its export revenue.

Talco, formerly TadAz, claims that Mr Nazarov and Ansol, his Guernsey holding company, siphoned more than $500 million (£315 million) in profits from the smelter between 1996 and 2004 through a corrupt relationship with the plant's former manager. It alleges that lavish bribes were paid including the gift of a £300,000 flat in Marylebone for use by the manager's son. It has also, in a separate action in the British Virgin Islands, accused Rusal, Ansol's former joint venture partner, of involvement in the fraud, although it failed in a bid to include the Russian company as a defendant in the case in London.

Mr Nazarov denies the allegations and has brought his own claim against Talco, claiming that he is owed more than $130 million since Talco severed its dealings with Ansol in December 2004. His lawyers will argue that he rescued the smelter at a time when it was running at less than half of its capacity and the country was in the grip of civil war. According to Mr Nazarov, he turned the plant around by brokering crucial supplies of raw alumina and securing buyers for the refined product, first in partnership with a wealthy Greek shipping family and later through barter agreements with Rusal and Hydro. Under his direction, Mr Nazarov claims, the plant channelled millions of dollars into community projects, building schools, roads and hospitals.

“The Tajik Government has desperately sought to discredit me personally, and my company, by making a number of ludicrous allegations, which are resolutely denied,” Mr Nazarov said.

According to disclosures made in court this year, Herbert Smith, the City law firm acting for Talco, expects to spend about £55 million by the end of the trial. Clyde & Co, representing Mr Nazarov, has projected costs of £22 million. Other law firms could add a further £10 million to the total. Lawyers fear that the case could encourage companies to fight legal battles in less expensive jurisdictions.

Herbert Smith declined to discuss its fees.

Explore Law

• Columnists

• Law Panel

• Law Reports

• Student Law

Times Recommends

• BGC 'set aside £40m to lure Tullett brokers'
• Legal aid review to ensure value
• Fears as 21 magistrates' courts face closure