Trade unions today called on the Prime Minister to apologise for what they describe as "irresponsible attacks and smears" on the NHS here in Wales.
They say UK government criticisms of the Welsh Labour Government's handling of the health service here damage the morale of staff and their relationship with patients.
There have been a series of negative headlines surrounding the NHS in Wales in recent months, over missed targets and complaints about standards of care.
Last week, it was revealed that ambulances only reached life-threatening incidents within eight minutes in 54.1 per cent of cases - below the 65 per cent target.
Last month, a report into Princess of Wales Hospital in Bridgend and Neath Port Talbot Hospital warned: "there are aspects of the care of older people which are simply unacceptable and must be addressed as a matter of urgency."
David Cameron has made repeated criticisms of how the Labour Welsh Government runs the health service here, particularly in clashes with Ed Miliband in the run up to the General Election next year.
His most high-profile comments came at the Welsh Conservatives' conference in Llangollen in April, when he said: "When Offa's Dyke becomes the line between life and death - we are witnessing a national scandal."
The Trades Union Congress, which represents around 400,000 workers across Wales, today called on the Prime Minister to apologise for that remarks - and wider comments around the Welsh NHS.
Sara Grinter from Barry received extensive treatment at the University Hospital of Wales for anorexia as a teenager, and now works there as a cardiology medical secretary.
She told us she thanks the NHS for keeping her alive, and is proud to work there, but constant criticisms of the service do have an effect.
Last year, we marked the 65th anniversary of the NHS with a number of special reports.
Welsh Labour have described David Cameron's comments on the NHS in Wales as a "shameless attack", and said "the dedicated workforce deserves better from the Prime Minister."
The Prime Minister has today refused to offer the apology demanded by the Welsh Trades Union Congress.
A Downing Street spokesman said: "The PM has set out his view on how the NHS is run in Wales and he stands by that."