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.
Southampton's heart unit was one of the facilities saved by the review, following the Daily Echo's 'Have A Heart' campaign which was packed by more than 250,000 people.
The Leeds 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 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.
''Fundamentally, this action is about making sure that children across the country have proper access to vital, life-saving services.
''We remain hopeful that common sense and democracy will prevail.''
A judge will now examine the evidence to decide whether SOS can go forward with the judicial review.
The consultation process was launched by the JCPCT of England as part of a national review aimed at streamlining paediatric congenital cardiac surgery services.
The Safe and Sustainable review followed the landmark inquiry into children's heart surgery at Bristol Royal Infirmary between 1990 and 1995, where up to 35 children and babies died as a result of poor care.
In the wake of the inquiry, it was recommended that paediatric cardiac units be set a target for the number of operations per year, and surgery be concentrated in a few specialist centres in order to ensure quality of care.
The institutions which will now house the specialist surgery centres are: Evelina Hospital, which is part of Guy's and St Thomas' Hospital Trust, Great Ormond Street, both in London, Southampton General Hospital, Birmingham Children's Hospital, Bristol Royal Hospital for Children, the Freeman Hospital in Newcastle and Alder Hey Children's Hospital in Liverpool.
John Radcliffe Hospital in Oxford was originally part of the consultation process but it suspended its children's heart programme in 2010 following a spate of deaths.
It is understood that implementation of the new services is expected to take place throughout 2013. Once the units stop providing surgery they will still see patients for diagnosis, monitoring and non-surgical treatment.
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.''