The treatment of Sir Roy Meadows, the paediatrician who gave evidence in the case of Sally Clarke, raises larger issues about how we protect the judicial process

An expert witness was brought before a professional conduct committee and accused of professional misconduct because of the evidence he gave in a murder trial. It led to the expert being struck off the practice register; barred from doing his job, losing his livelihood. It emerged later that he should never have been brought to such a committee, never mind going through a hearing, never mind being found guilty, never mind being struck off.

And because of this case the professional institutions and trade bodies in the construction industry will have to rethink their disciplinary rules. Those disciplinary procedures are unlawful and do more harm than good.

Let me come back to this particular case in a moment. First let me tell you of two construction industry incidents. A few years ago an expert chartered engineer gave advice about underpinning works needed for his client's building. As a result of this advice, his client sued the people who had built it. Shortly before the trial the expert conceded that his expert opinion was flawed. The other side's expert had pointed out mistakes in his report. Indeed he had fallen into error. He signed up to a jointly agreed report, and his client's case was torpedoed before trial. His client promptly sued the expert for negligent advice - and lost. The Court of Appeal said that even if there was negligent advice, the expert in litigation was conferred with complete immunity. Their first duty was to give truthful and fair evidence to the court. No threat of being sued for resiling from their first position should get in the way of backing down.

The second construction case was an allegation of design piracy. The judge said the expert witness made a blunder after blunder. He had him reported to his professional institution. It, by the way, threw the complaint out, but not before the disciplinary process had caused massive wear and tear to say nothing of expense, embarrassment and loss of business.

The plain fact is that in judicial proceddings an expert's blunders, mistakes, wrong headedness and/or stupidity are not enough to get them sued, nor are they grounds for that expert to be punished by their professional institution.

Nobody participating in the administration of justice shall be sued, prosecuted, or disciplined for blunders. There is total immunity

The murder trial is such a sad case. Do you remember how Sally Clark lost first her son Christopher in a cot death? Then she lost Harry in another cot death. She was tried and convicted of murder and given a life sentence. On appeal one of the things that came out was that Sir Roy Meadow, the paediatrician who gave expert advice, gave statistical evidence putting the chances of two cot deaths in these circumstances at 1 in 73 million. Mistake. Worse, the expert paediatrician was giving expert opinion in statistics when he was not a qualified statistician. Who knows if that evidence was what persuaded the jury to convict? The fact is that he had broken a key rule in opinion evidence - not to stray beyond your expertise. Sally Clark spent three and a half years in prison. Her appeal was eventually allowed on failure to disclose relevant evidence, not on Sir Roy Meadow's evidence.

Sally Clarke's father reported Sir Roy Meadow to the General Medical Council. That body found that the expert had not intended to mislead the court nor was there any evidence of any calculated or wilful failure to use his best endeavours to provide evidence. He had acted in good faith. Nevertheless he was guilty of breaching the rules for giving expert evidence, which they said was serious professional misconduct and erased from the medical register.

He brought the GMC to court. The GMC is now seeking leave to appeal against the court's decision. Nobody, whether judge, arbitrator, adjudicator, witness, expert witness or anyone else participating in the administration of justice shall be sued, prosecuted or disciplined for blunders. There is total immunity. It is part of the bedrock of English law.

How come? It is not for the benefit of individuals; it is instead for the overarching public interest … the need to ensure that the administration of justice is not impeded. This broad view is known as public policy. No witness shall be in fear of what they say as a truth. Making mistakes in a judicial process is not the same by a mile as being dishonest, calculating or recklessly indifferent so as to cause injury. All that is still a disciplinary matter.