An al-Qa'ida plot to crash an airliner into Parliament is being "swept under the carpet" by Scotland Yard, one of India's most senior policemen has claimed.

On Tuesday, Mohammed Afroz, 24, a trainee pilot, will be taken from a top-security Bombay prison to be charged in court with masterminding a plan to hijack a Manchester-bound aircraft and fly it into the House of Commons on 11 September.

According to the Indian authorities, the plot was abandoned when security was stepped up in the hours after the terror attacks on America. Six days later Mr Afroz, who was studying at the Cabair flight school in Bedfordshire, returned to India and was arrested at a Bombay hotel.

Indian police, who travelled to Britain to investigate the alleged suicide plot, have now criticised their British counterparts for not doing more to investigate Mr Afroz. They insist he was part of an underground Islamic terror ring in the UK. They also accuse Scotland Yard of refusing to arrest two British Asians claimed to be al-Qa'ida operatives.

"I feel this matter needs to be taken more seriously by the British police," said Bombay's most senior policeman, Commissioner M N Singh, who led a team to Britain last month. "I believe what Afroz says, based on the evidence from his passport of frequent travels and training in flight schools in Britain, America and Australia. If somebody wants to put it under the carpet, that's their choice. I don't want to. He has made a full confession in court and he is clearly not insane "

The plan to attack Parliament was allegedly mentioned by Mr Afroz in an email to Australia. British detectives flew to Bombay in December to investigate the case, but did not see Mr Afroz. Scotland Yard, which co-ordinates anti-terror policing for the UK, insisted it was taking the case extremely seriously. "We are continuing to liaise with the Indian authorities," a spokesman said. "We have not had access to Afroz but have asked the Indian authorities for access and are still awaiting a reply."

Indian detectives claim Mr Afroz confessed he got as far as the check-in queue at Heathrow, complete with a back-up squad of hijackers. It was only when they saw security had been beefed up after the attacks earlier in the day that he abandoned his mission and fled back to India.

The Indian police, who also went to Australia and the US during their investigation, have refused to name the British Asians they accuse of being al-Qa'ida operatives, but they are believed to be a businessman living in London and a man in Leicester.

Mr Afroz grew up in a Bombay slum, where his father works as a tailor. The police say their suspicions were aroused by the fact that a poor Muslim had spent tens of thousands of pounds studying at flight schools abroad, but his family insists he is a victim of post-11 September paranoia.

His elder brother, Mohammed Farooque Abdul Razzak, a customs clearing agent, said Mr Afroz's flight training had been paid for out of "black money" from illegitimate import deals. "Afroz is a very naive young man who wanted to be a pilot," he said. He claimed his brother's confession was made under torture, and that he had been denied access to lawyers.

"My brother was at his flight school on 11 September. He has nothing to do with al-Qa'ida. We've been plunged into a nightmare."

Mr Afroz's British uncle, Iqbal Shaikh, a Leicester taxi driver, described the accusations against his nephew as "rubbish". "The Indian police have made this up. He is a Muslim learning to fly, so he fits the bill."