David Blunkett blames his downfall on a millionaires' plot to destroy a 'working class lad who's the voice of ordinary people', friends disclosed last night.

In a deliberate attempt to launch a concerted fightback against Kimberly Quinn, Blunkett's former lover, a close associate of the former Home Secretary said that she appeared to have 'mesmerised' Alan Budd - the civil servant investigating claims that Blunkett fast-tracked a visa for her Filipino nanny.

Accusing her of acting through 'personal spite', the friend said Blunkett had been the victim of an orchestrated campaign against him originating from the publisher Condé Nast, which employs Quinn's husband Stephen.

'There seems to be a big disinformation campaign starting almost immediately from Condé Nast and the people supporting her,' the friend said. 'It's very much the American millionairess who's managed to knock out the working-class lad who's the voice of ordinary people.

'So be it. What is interesting is that it would appear that Alan Budd appears to have been as mesmerised by Kimberly as he [Blunkett] was.'

The inference that the pregnant Quinn could have worked her charms on the senior civil servant from her hospital bed will cause consternation at Westminster, where there is mounting concern for the emotional welfare of the distraught Blunkett.

The friend joked: 'If they'd actually planted her it would be sort of a Secret Service plot: you couldn't have made it up, could you? At some point, a film will be made about all this.'

But with Budd due to report on Tuesday, a less flattering version of how the Home Secretary was forced out was this weekend emerging from within the Civil Service. Senior Whitehall sources accused Blunkett of running a 'regime of fear' in which officials felt intimidated into doing his bidding, reflecting allegations understood to have been forwarded to the inquiry.

'The guy was a bully,' said the source. 'That isn't to say he didn't have some personal charm, but people were almost frightened of him.'

Budd is expected to confirm on Tuesday that, contrary to Blunkett's initial denials, he did send paperwork relating to nanny Leoncia Casalme's application to stay in the UK to his private office. It was subsequently forwarded to immigration officials and the case was processed more quickly than it would otherwise have been.

Blunkett is understood to have maintained that he highlighted the letter only as an example of how applicants in general were still facing delays, even though backlogs were meant to have been cleared, and did nothing improper.

His resignation has shifted the spotlight on to the role of his civil servants, with Budd under pressure to establish why officials speeded up Casalme's case - and whether they felt under undue pressure to do so.

Blunkett resigned last Wednesday, after Budd - having taken testimony from Quinn - uncovered a paper trail that showed the former Home Secretary had given an inaccurate version of his role in the Casalme case. He is said to be a 'broken man', with friends alarmed that he is losing weight and appears physically and emotionally exhausted.

If, as the former Home Secretary's friends believe, he is found to have acted in good faith, then the general election co-ordinator Alan Milburn is preparing to offer him a role as a key 'face' of the campaign expected next spring or early summer.

However, Blunkett's initial apparent failure to remember what he did with the nanny's paperwork, and the serious discrepancies in his initial account unearthed by Budd, have alarmed some colleagues who fear his distress is clouding his judgment. 'David has been under such immense emotional pressure and stress for months now. The memory is a very strange thing,' said one Cabinet source.

Blunkett's departure, and the ensuing hasty reshuffle, have renewed tensions between Tony Blair and Gordon Brown, with the Chancellor infuriated by what one source close to him called the 'aggressive and divisive' briefing surrounding it - with Blairites suggesting it marked a major advance for their footsoldiers.

David Miliband, the schools minister, is also understood to have resisted his move to Milburn's team. Private Downing Street polling suggesting that the affair has played badly with the public was confirmed last night by a YouGov poll for the Sunday Times, which showed 68 per cent of voters thought the Prime Minister had been damaged by it.

While the majority thought Blunkett was right to have resigned, almost two thirds thought Kimberly Quinn had acted vindictively.

'Nannygate' began last month, when an email from Kimberly Quinn referring to a visa that 'David fast-tracked' became public. The inquiry discovered that Quinn had handed on to the then Home Secretary a letter sent from the Immigration and Nationality Directorate telling the nanny she would have to wait up to a year for her case to be processed.

Blunkett sent the letter to his private office, which forwarded it to IND officials the next day. A week later, a civil servant sent an email to IND inquiring about the case - and was told, in an email sent the next day, that it had been done with 'no favours, but quicker'. The nanny received permission to stay in Britain within the week.

Crucially, Blunkett is now said to remember handling the letter and raising it with senior immigration officials, although he insisted to friends that he raised it because the backlog was meant to have been tackled to eradicate such delays.

Friends of Blunkett last night dismissed suggestions that he had bullied civil servants, arguing that 'every single member of his private office was in tears' when he resigned.

He is, however, said to believe that he has enemies in the senior echelons of the immigration department.