Parents have reacted with anger at recommendations to stop children's heart surgery at an Oxford hospital.
The John Radcliffe Hospital came bottom in an NHS review into how well prepared for the future were the 11 hospitals in England which offer the surgery.
It comes after surgery was suspended at the hospital when four children died in three months.
Maria Crocker, whose eight-year-old son David is waiting for an operation, has launched a campaign.
Earlier this year a panel of experts conducted a review to assess the ability of the children's heart surgical services to meet new quality standards.
The review, led by Professor Sir Ian Kennedy, said proposals were designed to improve safety by having fewer, more specialised sites.
Mrs Crocker said it was important for "a family network" to be around children when they undergo surgery.
Mrs Crocker, from Wallingford, said her son had to take medication to control his condition, which was serious but stable.
Under the changes he would still attend check-up appointments at the hospital, which will continue to provide specialised cardiology services for children, but would have to travel to another hospital for surgery.
"I'm absolutely devastated that they could even comprehend this," she said.
"It's more than likely he's going to have to go to Southampton, that's where a lot of the operations at Oxford are going to.
"It should be Oxford, it should be where his family is and where his grandparents are, it should be where his family network is."
Her concerns were echoed by mother Fiona Spensley, who said her daughter Sophie would have died on the way to hospital if she had been taken further afield for surgery when her heart stopped three times.
A surgeon at the hospital fitted her with a pump which kept her alive for 12 days - allowing her own heart time to heal.
"This re-organisation will not necessarily save any lives, they haven't proved it," she said.
"This is dreadful news for Oxford and dreadful news for children with heart problems in the country.
"What we have got now is is a very able cardiac surgeon and cardiac interventionist at Oxford who will be unable to operate on children.
"We are losing very, very sorely needed paediatric cardiac surgery."
The hospital said a final decision about the future of the service and its other current services would not be made until the outcome of a public consultation in 2011.
Review member Leslie Hamilton said: "The NHS review will ensure that wherever possible services such as assessment, diagnosis and ongoing care are provided as close to people's homes as possible.
"However, we must ensure that children who need heart surgery receive care in centres that meet the highest standards."