Birmingham MP John Hemming was accused yesterday of abusing his position in a scathing attack by one of the country’s top family law judges.
Lord Justice Wall said the MP’s behaviour was "not only unacceptable but shocking".
The condemnation followed Mr Hemming’s long-running campaign for reform of public family law, which has included the release of a pop single to publicise his cause.
The judge said: "As to Mr Hemming, my judgment is that his self-imposed role as a critic of the family justice system is gravely damaged.
"Speaking for myself, I will not be persuaded to take seriously any criticism made by him in the future unless it is corroborated by reliable, independent evidence."
Mr Hemming (Lib Dem Yardley) has accused social service departments of removing children from families unnecessarily, so they can be put up for adoption. He has also argued that the secrecy in which family courts operate prevents proper scrutiny of decisions.
In a hard-hitting speech last month in the Commons, Mr Hemming said: "In the deep, dark corners of the British legal system, hidden away by threats of imprisonment for those who speak out about injustice, we have allowed bad practice to fester.
"No action can be taken by a Member of Parliament to prevent solicitors from undermining their own clients because they want to keep the money coming in from the local council.
"No action can be taken by an MP to stop social workers who lie to the courts because they want to win a case and hit their adoption targets, or to stop doctors who provide rubbishy, unproven and unchallenged medical evidence that destroys families, but fills their bank accounts."
But Lord Justice Wall was equally outspoken, as he delivered judgment at the Court of Appeal in London yesterday.
He was ruling in the case of a woman whose child had been taken into care by Nottingham City Council. Mr Hemming had attended court hearings as the woman’s adviser.
The judge said: "Mr Hemming has been willing to scatter unfounded allegations of professional impropriety and malpractice without any evidence to support them."
Referring to criticism the MP levelled against a clinical psychologist involved in the case, identified only by the initials HJ, Lord Justice Wall they were "a wholesale and entirely unwarranted attack on the professional integrity of HJ for which, once again, there is no evidence whatsoever".
The judge also referred to a parliamentary petition in which he said Mr Hemming indicated he believed the psychologist was in the pay of the local authority, and that he considered the system under which the woman’s case was being handled was "evil."
Lord Justice Wall said: "In my judgment, these comments are not only wrong and ill-informed. The simple fact remains that they have no foundation in the evidence presented either to the Nottingham County Court or to this court. That they are made publicly by Mr Hemming once again strikes me as an abuse of his position."
The judge ruled that Nottingham City Council was right to take the child, identified only as KP, into care.
And he said Mr Hemming had concentrated too much on the rights of the mother and failed to take into account the welfare of the child.
He said: "The danger of the mother’s approach, reinforced as it has been in my judgment by Mr Hemming’s partial and tendentious advice, is that it has been entirely adult focused. Not once in his argument did he mention the welfare of KP."
Last night Mr Hemming said: "I have been very critical of the judicial process in Public Family Law.
"I refute the criticisms in the Court of Appeal. But there is something far more important than whether or not my allegations are true."
He said a judgment had been made without the mother receiving an opportunity to present her case. "The mother . . . has been given no opportunity to challenge the allegations of the local authority.
"This is a case that must be considered by the House of Lords."
Mr Hemming’s single is to be released worldwide on May 19. The first verse, written before yesterday’s judgment, refers to the case, having changed the mother’s name to "Sarah".
The MP sings: "Sarah they said was slow; So her babe she had to go. In court the experts said; They turned the truth right on its head."