A decision is expected in the High Court later on the legality of proposed changes to children's heart surgery services.
The ruling, which should be delivered this morning, could have implications for the future of surgery at Southampton General Hospital.
Last year Southampton's Children's Heart Surgery Unit - one of the country's best - had just a 1 in 4 chance of being selected as one of six specialist cardiac centres.
Operations at the John Radcliffe Hospital in Oxford had already been stopped with families there backing Southampton's campaign.
But there was joy as Southampton was chosen as one of the specialist centres.
However, the original ruling could be overturned if a legal challenge is successful.