A dentists' union is launching a legal challenge against the Government's decision to appeal against a judicial ruling that dentists cannot be sacked without reason.
In April 2006, West Midlands orthodontist Dr Eddie Crouch took legal action against South Birmingham Primary Care Trust over a contract which included a clause saying his contract could be terminated without reason.
Two years later - in February - the High Court ruled in favour of Dr Crouch, saying that it is unlawful for primary care trusts, which commission health services locally, to end dentists' contracts without cause.
The Department of Health (DoH) is appealing that decision.
The British Dental Association (BDA) is now lodging papers at the High Court in London against the DoH's appeal.
Peter Ward, chief executive of the BDA, said: "Effectively the department is saying that a primary care trust should be able to say to a dentist: 'Your contract will come to an end tomorrow, just because we feel like it'.
"Every right-minded person can see that this is totally unreasonable and would destroy the viability of family dental practices.
"A success for the Department of Health would be bad for dentists, bad for patients and disastrous for the health of the nation."
The union says that it is "disappointed" the DoH has launched the appeal.