Srichand Hinduja is alleged to have 'paid' for a British passport

Srichand, Gopichand and Prakash Hinduja have been accused of criminal conspiracy and bribery in connection with the purchase of field guns by India from the Swedish company, Bofors.

On Friday, a court granted the multi-millionaire brothers bail on condition that they did not leave the country without permission.

The three deny the charges, arising out of a lengthy Indian police investigation, which also implicated a number of prominent politicians including the former prime minister, Rajiv Gandhi.

'Passport money'

In a separate development, Srichand Hinduja denied reports that he donated about $1.5m (�1m) in order to obtain a British passport.

Mandelson denies having intervened in favour of Mr Hinduja

The Observer newspaper alleged that a British minister, Peter Mandelson, helped Mr Hinduja obtain citizenship after the businessman agreed to help finance London's Millennium Dome.

The newspaper said the minister - at the time in charge of the Dome - had stepped in after Mr Hinduja's first application failed. He received a passport six months after his second application.

Mr Mandelson has denied the charges, saying the application had not been supported or endorsed by him.

Permission to travel

The brothers were interrogated by Indian detectives over the weekend about their involvement in the Bofors case.

The scandal surrounds the purchase of artillery guns

Judge Ajit Barihoke ruled on Saturday that the interrogation could continue for a few days if necessary.

The brothers have applied for permission to go abroad to attend board meetings of various companies, but the CBI has said they should surrender their passports and remain in India.

One of the defence lawyers, Rajinder Singh, said the fact that the brothers had appeared in court voluntarily was an assurance that they would not avoid trial proceedings.

Judge Barihoke has said he will give a ruling on Monday.

Key case

The brothers - two of whom are based in the UK and the other in Switzerland - arrived in India earlier this week after being named in a charge sheet by the CBI.

The charges followed a battle by the CBI to gain access to confidential bank account records held in Switzerland, which the agency finally won last year.

The Bofors corruption case is regarded as one of the most important India has ever seen, with a number of other international businessmen and Indian politicians implicated.