'Parliament is deadlocked on serious issues that may end up in a 'ping pong' test of wills'

Where did we get with the Mental Health Bill, that heavy ball and chain around ministerial ankles for most of the past decade? I know how important it is, but feel that sense of burden. Such passion aroused on both sides, such indignation against those who share concerns but disagree as to remedies.

The short answer is that the latest, shorter version of the bill started its career in November in the House of Lords, where it was amended by a cross-party coalition. It has now been through its Commons second reading and detailed committee stage and is due back for final stages - and a showdown with the peers - any day.

What will happen? Much remains to be resolved. Ministers have made some concessions, including the need for fundamental principles and the code of practice to be entrenched, as well as separate facilities to treat under-18s, although health secretary Patricia Hewitt warned MPs the Lords are being too prescriptive.

The sentiment is mutual. 'I would like to hear more tolerance towards the Lords' amendments and towards the Mental Health Alliance,' Dr Richard Taylor, the independent MP for Wyre Forest, told me.

'The government always gives the impression of being adamant. It uses brinkmanship to show it is fighting to protect the public,' complains another MP-medic, Liberal Democrat Dr Evan Harris.

Some Labour MPs agree with these implicit charges of 'lock up the nutters' populism, an echo of other Blairite manoeuvres to wrong-foot the Tories, on law and order, for example. Having spoken to health ministers over recent months, I remain unpersuaded. A lot of the differences are technical, ones on which experts of goodwill can disagree. I realise that most expertise is lined up with the alliance against Ms Hewitt and health minister Rosie Winterton. That does not always make them wrong.

Even when the government insisted on broadening the range of medically qualified professionals - not just doctors - able to act as the 'responsible clinician' in mental health cases, some peers and MPs accused it of deliberately seeking to split the alliance as the professions that would benefit peeled off. That is what happened, but I doubt whether 'driving a wedge' was the prime motive. Naive or what?

Whatever the motives, Parliament is still deadlocked on serious issues that may end up in a 'ping pong' test of wills between the Lords and Commons (the elected house usually prevails) unless common ground can be found. One is the issue of 'impaired decision-making' - as distinct from 'mental disorder' - whereby the Lords protected from compulsory detention or treatment those rationally capable of refusing it.

Ministers expect the Lords to give in on that one. 'Their position is close to telling people in trouble to go away and commit suicide,' says one Labour loyalist. But on the crucial issues where critics complain there is still insufficient balance in - between civil rights and public safety - there is no deal yet in sight.

One such issue is exclusions from the definition of mental disorder. The peers have specified substance abuse, sexual identity, illegal acts and cultural, religious or political beliefs as not attributable to mental disorder. Ministers say that will merely create a lawyers' paradise. Peers apparently argue that their fears apply to unknown future governments who might lock up dissidents, or to Commonwealth states that sometimes copy UK legislation.

Last, but far from least, is the replacement of 1983's 'treatability test' with 2007's 'appropriate treatment' - in hospital or via community treatment order. By 186 votes to 115, the Lords insisted such treatment must have therapeutic benefit, fearful that patients could be detained or placed under a virtual control order indefinitely.

Many Australian and US states now have forms of community treatment orders. So does Scotland, the critics concede. But they all have fewer powers and more safeguards. Dr Taylor remains bothered by this and is taking advice. 'I'm worried because if you detain people you cannot improve, then you gum up the system so that you can't treat schizophrenics who can be improved,' he told me recently.

There are compromise amendments around. But don't hold your breath.