Campaigners have reached their target of collecting 100,000 names in an on-line petition pushing for a re-think on the future of children's heart surgery at Glenfield Hospital.
Under Government rules it now means the issue is eligible for debate in Parliament and local MPs have now promised they will lobby to get the matter aired in the House of Commons.
Giles Peek, a consultant children's heart surgeon and head of the heart centre at Glenfield Hospital, said: "I'd like to say thank you to all the patients, families and members of the public for making their feelings known about the need to keep children's heart surgery in the East Midlands.
"I am sure my colleagues will be comforted to know that while they continue with the day job of caring for our poorly patients, their hard work and the life-saving services they provide to children all over the country is very much appreciated."
Campaigner Robyn Lotto, from Stoneygate, said: "This is not just a fight for our local unit. It is a fight to ensure that decisions are based on up-to-date and accurate data to ensure the safety of any change.
"We want to protect our children's futures."
Adam Tansey, from the Leicestershire-charity Keep the Beat, who set up the petition, said: "It is an amazing achievement to get 100,000 signatures. People said we wouldn't do it, but we have.
"It was set up 14 weeks ago which means that between 6am-10pm every single day the petition has been open someone has signed every minute.
"This demonstrates how strong the feeling is for keeping children's heart surgery at Glenfield."
Mr Tansey, from Burbage, whose three-year-old son Albert was born with half a heart, set up the petition in July.
It followed a national review of children's heart surgery in England.
The review decided that only seven out 11 hospitals in England should carry on providing surgery for children born with heart defects.
The service at Glenfield is now earmarked for closure.
It means children's heart surgery and the children's Ecmo service will move to Birmingham.
The Leicester Mercury has backed parents, councillors, children and staff fighting to get the decision reviewed.
Backbench MPs will now lobby the Parliamentary Backbench Business Committee to have the matter debated in the House of Commons.
One backbencher, Jon Ashworth, Labour MP for Leicester South, said he would today start the process calling for a debate.
"Some people thought the petition would never reach 100,000, but it has and it is important there is a full public discussion."
Liz Kendall, a Shadow Health Minister and Leicester West MP, added: "I will be backing and working with MPs to make sure this matter is debated in Parliament."
Nicky Morgan, Conservative MP for Loughborough, said: "I am still hopeful that the Glenfield Heart unit will be saved.
"The Ecmo service there makes such a difference I don't see how the health service nationally can do without it."
The online petition can still be signed by going to:
http://epetitions.direct.gov.uk/petitions/35788
