The minister's name appears on a list of alleged clients of a disgraced stock market manipulator, Jonathan Bekhor, who fled the country owing millions of pounds. Lawyers representing Michael Allcock, a maverick Inland Revenue investigator, claim that he was in the process of examining those clients when charges were levelled against him.
Mr Allcock, who was blamed by the fugitive businessman Asil Nadir for bringing down his Polly Peck empire, is expected to stand trial in September. In July he was committed for trial on 14 charges of corruption and five of theft. Two businessmen were also committed for trial on related charges.
An Inland Revenue investigation team led by Mr Allcock was pursuing individuals thought to have used offshore companies to avoid paying tax on massive City share deals. They are said to have deposited profits from share dealings in bogus companies based in tax havens, then arranged for the money to be brought back to Britain in cash.
The accused, the former boss of the secretive Special Office 2, employed unorthodox methods to track down tax evaders, and was credited with retrieving pounds 100m of formerly lost revenue. His methods involved doing "deals" with wealthy foreigners who used Britain as a base but paid no tax.
The 47-year-old from Colchester in Essex has spent more than three years waiting for his case to be resolved. Following his suspension in 1992, he was investigated by the police and finally charged in January 1994.
Lawyers are expected to argue about sensitive information contained in the hundreds of tax files released by the Inland Revenue for the case. Those already made available show signs of having been censored "on the grounds of public interest".
A spokesman for the Crown Prosecution Service said the Public Interest Immunity restraints sought by the prosecution differed from those criticised by Sir Richard Scott and did not require ministerial signatures. Some information would also be restricted by the Inland Revenue's governing principle of taxpayer confidentiality.
It is understood that the identities of the minister and prominent Stock Exchange figures could be kept secret by an agreement between lawyers to refer to individuals by codenames only.Reuse content