A campaign group has launched legal proceedings against NHS officials who made the decision to close a children's heart surgery unit.
Save Our Surgery (SOS) said it has filed for permission for a judicial review against the decision made by the Joint Committee of Primary Care Trusts (JCPCT) to close the unit at Leeds General Infirmary.
In July it was announced that the hospital, alongside Glenfield Hospital in Leicester and the Royal Brompton in Chelsea, west London, would stop performing the specialist surgery in a move to streamline paediatric heart services.
Officials decided to close the three surgical units after an NHS review concluded that expertise was spread too thinly in the 10 sites and should be concentrated in fewer hospitals.
The SOS campaign group, made up of parents of patients and clinicians, said it is disputing the legality of the JCPCT decision.
The group said that children from the Yorkshire and Humber region with heart problems - some of whom will be in a critical condition - will have to travel as far as 150 miles for treatment. They are also questioning the JCPCT's decision-making process. The group said that the scoring system used to compare the hospitals was flawed.
SOS spokeswoman Sharon Cheng said: "It's with great regret and reluctance that Save Our Surgery has decided to lodge this application for legal action against the decision to close the Leeds children's heart surgery unit. Quite simply, we feel we've been left with no alternative after all other options put forward were rejected outright by the senior NHS officials responsible."
A judge will now examine the evidence to decide whether SOS can go forward with the judicial review.
Sir Neil McKay, chairman of the JCPCT said: "The attempt to launch legal action flies in the face of the support that our decision has received from royal colleges of medicine, expert doctors and nurses and national charities across the country. I realise that this is a sensitive issue in Yorkshire and the Humber but I sincerely believe that after 12 years of waiting for this difficult decision, we must all now focus our efforts to prepare for implementation by working together.
"However, if the court decides that it is necessary, we stand ready to defend our process and our decision with confidence."