Inexorably the balance of probability is tilting against the Family Law Bill becoming law.

Initially thought to be progressive and non-controversial, this flagship for the Lord Chancellor, Lord Mackay, has become a millstone around the government's neck.Growing disenchantment with the direction the Bill was taking culminated last week in the withdrawal of support of the Law Society's family law committee and the Solicitors Family Law Association.

Although Cardinal Basil Hume reiterated his support this week, he was one of only a handful of prominent non-politicians still prepared to back the legislation publicly.Predictably, the Society's pull-out provoked an angry reaction at the Lord Chancellor's Department.

Jonathan Evans, the beleaguered parliamentary secretary, hit out at the decision, accusing Chancery Lane of looking to its own interests rather than having 'any desire to see an improvement in family law in this country'.

Hilary Siddle, chair of the family law committee, struck back, describing his remarks as 'unseemly and unjustified'.

The committee will recommend sweeping changes to the Bill at report stage.Other organisations appeared to have misgivings.

The National Society for the Prevention of Cruelty to Children said that the Bill's principles had been 'diluted' and that the proposed legislation now 'worked against the best interests of children'.

The Body Shop chain of stores, which has campaigned in support of the Bill's domestic violence provisions, was reported to be Treconsidering' its position.

Mediators, on the other hand, were less willing to relinquish what they regarded as a valuable and overdue recognition of the importance of their field enshrined in the Bill.

Thelma Fisher, director of the National Family Mediation organisation, said she 'regretted' the Society's withdrawal.

Alastair Logan of family specialists the Logan Partnership and chairman of the British Association of Lawyer Mediators (BALM), had many concerns.

But he said: 'There is still time to salvage a piece of legislation that virtually anyone working in the field thinks is sensible.' Elsewhere within the profession, the Family Law Bar Association (FLBA) was unwilling to abandon the Bill's domestic violence provisions, which were taken from the Family Homes and Domestic Violence Bill, withdrawn by the government last year.

Although the FLBA agreed that the Family Law Bill was 'much less satisfactory' than before, 'we have made no decision as an association that we are withdrawing support', said its chairman, Elizabeth Lawson QC.The final straw for the Law Society's support came in standing committee in the House of Commons earlier this month, when a coalition of MPs, Conservative and Labour, led by Edward Leigh, forced several changes on the government.

Earlier, the Bill's original 12-month waiting period P which had survived several attempts to extend it in the House of Lords P was extended to 18 months after more than half of all Tory MPs, including 22 ministers, broke ranks in a free vote.Part icularly galling was a concession to Mr Leigh's 'moral majority' campaign, involving an additional minimum three-month period for 'reflection and conciliation' before a statement of marital breakdown could be filed.

The Society argued that a waiting period totalling 21 months could put 'intolerable additional burdens on divorcing couples and their children'.

Yet it was thought likely that a bid would be made to reverse the amendment in the House at third reading.There had been some lobbying victories for the Society.

The Lord Chancellor agreed that the presumption in favour of mediation in legally aided cases would be removed.

Also, during the 'information meetings', couples would be told of the availability of legal advice and representation.

But, in a rebuff to the Society, a second, compulsory 'mediation meeting' was tacked onto the end of the first three-month cooling-off period.Labour backed the abolition of fault in divorce from the beginning, and the government has depended on this support when threatened by its own backbenchers tabling wrecking amendments.

A Labour amendment on splitting pensions upon divorce, which was imposed on the government in the Lords, was considered a great asset to the legislation.In recent weeks, however, Labour's legal affairs spokesman, Paul Boateng, has shown increasing hostility to the Bill, variously labelling it a 'dog's breakfast', a 'Frankenstein creation' and 'friendless'.

Although many Labour MPs are known strongly to support the Bill's no-fault and domestic violence provisions, others are angry that their party is 'propping up' the government over a measure that generates little public enthusiasm.

Labour leader Tony Blair has publicly condemned the Bill for being insufficiently child-centred, but is thought to be wary of exposing Labour to government attacks if his party helps vote down the Bill at third reading.Options understood to have been discussed include a Labour abstention at the third reading, due to take place in June.

This would leave the government a chance of passing the measure if it can marshal enough support within its own ranks.To appease those Labour MPs who want to maintain support for the Bill, the leadership could make a commitment to reintroduce the Family Homes and Domestic Violence section of the Bill once in government.

Among Conservatives, reserves of enthusiasm for the Bill are understood to have dwindled to almost nothing.

Parliamentary sources say some previously supportive government ministers would be relieved if Labour killed off the Bill.

For the Lord Chancellor this would probably mean resignation.

Caught between the task of shepherding through Parliament what is widely thought to be unworkable legislation and the threat of a humiliating public defeat, Lord Mackay must wish he had never introduced the Bill in the first place.