Campaigners fighting to save the children's heart unit at Leeds General Infirmary (LGI) have called on Health Secretary Jeremy Hunt to launch an investigation into the suspension of surgery at the hospital, describing the decision as "NHS politics at its worst".
Some operations at the centre will restart on Wednesday - nearly a fortnight after they were halted following the intervention of Sir Bruce Keogh, the medical director of NHS England.
On Monday, NHS England announced a phased resumption of surgery following the completion of a first stage of a review into services.
The decision to suspend surgery last month after concerns were raised over death rate data and other issues caused a huge controversy, especially as it came a day after a group campaigning to save the Leeds unit from permanent closure won an important victory in the High Court.
That group - Save Our Surgery (SOS) - called on Mr Hunt to launch an independent investigation, saying it feared it was "no coincidence" Sir Bruce's intervention came just after the judge's ruling.
SOS campaigner Sharon Cheng said: "Given that the suspension potentially put patients at risk, has caused huge inconvenience and added stress to the families of children who have had to be treated elsewhere, and created unnecessary worries and fears amongst previous patients' families, questions must be asked as to why operations were suspended in the first place.
"We fear it's no coincidence that the action was taken on the day following the High Court verdict quashing the decision that Leeds should stop surgery, as part of the Safe and Sustainable review."
Mrs Cheng went on: "We hope those who made this decision will now be held to account. This whole exercise has been NHS politics at its worst. We call on the secretary of state to launch an urgent inquiry into these events and what led them to happen."
Earlier, Sir Bruce said children's heart surgery at the LGI was halted because of poor data showing unusually high death rates which were submitted by the hospital itself. He said that such drastic action was needed given the recent scandals at Stafford Hospital and in Bristol, which had occurred while doctors and managers "prevaricated" over what data meant.
Leeds North-West MP Greg Mulholland reiterated his call for an inquiry into what he called "this fiasco". He said: "I have written to the Secretary of State and asked him to order a full investigation into this closure and I am very pleased that the 'Save our Surgery' campaign are now calling for this as well and support them in that."