It has become almost a requirement in Labour circles to admit to some sort of mental instability. Whether it is a bipolar disorder or simple depression, you can't be a true member of the new Labour tribe, apparently, until you have had a nervous collapse. First, Alastair Campbell admitted that he has spent most of his adult life fighting mental illness. He feared it would overwhelm him during the Hutton inquiry into the dossier on Iraq's "weapons of mass destruction". He did not tell us whether he was suffering from any delusional condition when he helped write it.
Then, David Blunkett laid bare the depression he felt during the crisis that forced him out of the Home Office in December 2004. Former colleagues have noted the lack of judgement he has shown in publishing his diaries while the government is in a state of turmoil. By likening his suffering at the hands of the media to a soldier in the trenches during the First World War, or his family to victims of the Stasi, he comes across as distinctly paranoid.
More worrying is Blunkett's troubled state during much of his latter period in the cabinet. For Tony Blair to suggest that a return to the cabinet as work and pensions secretary would be helpful in rebuilding Blunkett's life also raises questions about the Prime Minister's own judgement.
The fragility of the human mind has been a constant theme of the sniping around this government. Gordon Brown's supposed "psychological flaws" were always as much of a projection of the fears of those calling the Chancellor names as they were an accurate assessment of Brown's state of mind. Being seen as weak has always been one of the cardinal sins of new Labour, but it turns out that two of the toughest nuts, Campbell and Blunkett, were barely holding it together at times. Paradoxically, the person often thought to be the source of the "psychological flaws" quote is Campbell, the one person at the top of government to have been officially diagnosed with such flaws. And yet he makes an important point for employment practice, society and politics, in praising Blair for hiring him in full knowledge of his past history.
It may have seemed in recent weeks as if large sections of the Parliamentary Labour Party were suffering from some form of collective madness as they bared their souls over the succession in public. It is all too glib to slip into a particular language when describing ministers: Blair has "lost it", John Reid is a "psycho", John Prescott is "a bit of a nutter" and Brown is "autistic".
Yet this language has never been far from the lips of the politicians themselves. From the "moment of madness" that drew Labour's first Welsh secretary, Ron Davies, to cruise Clapham Common in 1998, through Peter Mandelson's seriously unhinged "fighter not a quitter" speech at Hartlepool after the 2001 election, to the present admissions, there has always been the spectre of incipient madness hanging over this government.
Why this should be is something of a mystery. Perhaps Conservative politicians, because they always felt they were born to rule, have appeared better able to cope with the rigours of high office. Or maybe they, too, were just keeping up appearances.
One might have thought that a government with such a direct relationship to mental illness would have been better able to deal with the single area of policy where it threatens public safety: the criminal justice system. Some studies suggest that 90 per cent of offenders have some form of psychological disorder.
In the very week that the former home secretary admitted to having grave concerns about his own sanity, the prison population in England and Wales reached a new record of 79,843, little more than 100 short of operational capacity. The Prison Officers' Association, the probation union Napo, the Howard League for Penal Reform, the Prison Reform Trust, Inquest and the former chief inspector of prisons David Ramsbotham have all told the government that far too many people in need of treatment for mental illness are being warehoused in our prisons and most should not be there at all.
Staff in the prison and probation services are often expected to act as psychiatric nurses and drug treatment counsellors, as well as look after dangerous criminals. The situation is desperate. In some women's prisons, staff I have spoken to have spent whole nights cutting down inmates from home-made "ligatures" they have used to try to kill themselves.
But we don't even know the true scale of the problem. The most recent Home Office figures on mental illness among convicted prisoners come from 1998. Further long-term research, following 4,000 prisoners over several years, was commissioned last year. But that will not be ready until 2009, by which time the mental health crisis in the criminal justice system (and the cabinet) could be even worse than it is now.