It seems common sense that if someone during the FtP process has deliberately lied or caused harm to you that you should be able to prosecute them for defamation of character.
Unfortunately, there is an extremely old law, dating back to the days of William of Orange, that prevents anyone working for or giving witness to a public body being prosecuted in this way.
“Absolute privilege is a complete defence to an action for defamation in English law. If the defence of absolute privilege applies it is irrelevant that a defendant has acted with malice, knew information was false or acted solely to damage the reputation of the plaintiff.”
Vasanta Suddock is a nurse who managed to overturn a strike-off order in the High Court following her self-litigating. She overturned over 43 charges against her. She then went on to pursue the NMC in the courts for defamation. The judge made some very supportive comments but said until the absolute privilege law is changed there is nothing that can be done. She is trying to challenge this through the European Court of Human Rights. Read more about the case here
Of course, we want those in public office to be able to speak freely without risk of prosecution, but this needs to be balanced with proportionality against fairness. The NMC has not, to date, pursued her to reclaim the costs but this is always a risk of registrants when they continue to pursue cases on the basis of defamation.
You can, however, look at civil actions around human rights, breaching privacy and the right to family life but we would recommend you get strong legal advice before looking at this – the NMC have much bigger legal teams and resources so you need to match that with relevant expertise.