In the coalition era, PMQs has become a pretty unedifying event. But, this week, it sank to a new low.

In the Prime Minister's absence, his Deputy picked up the Cameron textbook and followed it to the letter. In fact, he took it to a whole new level. Most of his replies did all, or a combination, of the following: evade the question; blame Labour; distort the facts; and celebrate a coalition policy unconnected to the original question.

Clegg's pantomime-style gestures to the massed Tory ranks behind him, inviting cheers for policies he and his Lib Dem MPs were never given a public mandate to support, will not quickly be forgotten.

But he did do one thing that may in the end prove beneficial. Clegg's incendiary claims about NHS privatisation have at last ignited a debate which the country desperately needs to have at the coming election. Because it certainly didn't happen last time out.

In this parliament, NHS policies have been introduced that were in neither the Tory nor Lib Dem manifestos. The pace of change is now accelerating: only this week the BBC reported that, of 3,494 contracts let between April 2013 and August 2014, 1,149 contracts (33 per cent) have gone to the private sector.

The NHS is changing fast and the country needs to decide whether it supports these changes, because there is a real danger that, by the 2020 election, they will be irreversible.

Clegg's opening gambit in this important debate attempts to divert attention from what his own party has done by making audacious claims about Labour. His claim - Hinchingbrooke Hospital - the only NHS hospital to be privatised, and by the Labour party - is, as I will show, simply untrue. But, if this debate is to be of a quality that the public deserve, then they do have a right to ask all parties and politicians to account for past policy decisions in this area and what they would do in future if elected. I accept that challenge on behalf of Labour.

I was involved in health policy from various vantage points throughout most of Labour's 13 years in office, from working for the NHS Confederation in 1997 to Health Secretary in 2009/10. I am well-placed to account for what we did.

Back in 1997, the relationship between the NHS and private sector we inherited was one where the latter traded off the failings of the former. People were routinely told that they would have to wait months or even years for operations on the NHS. But, if they were prepared to pay, they were often offered the operation the following week by the same consultant.

Labour set out to end this scandal - and we did. Our drive to bring down NHS waiting lists began to change the nature of the relationship with the private sector. As the NHS improved, so the private sector's main selling point began to disappear. This led to a big change in the relationship where the private sector threw its lot in with the NHS in a supporting role, making its capacity available to bring down NHS waiting lists even further.

By the end of the last decade, the NHS had the lowest-ever waiting lists in its history. I am proud of that achievement by the last government and my role in it. But, by then, a difference of opinion had opened up. Some were arguing for the continued development of the relationship with the private sector and further steps to increase choice of providers through the Any Qualified Provider concept.

I believed that approach, in an era of flat funding, would prove very damaging to the public NHS. So, in late 2009, I changed Labour policy on the NHS and the private sector from Any Qualified Provider to NHS Preferred Provider. I did this for a number of reasons.

First, I believed the AQP approach would take the NHS in the wrong direction: towards fragmentation of care when the future demanded the opposite - integration. The logical consequence of it is to bring an ever-increasing number of entities onto the pitch dealing with one person's care, intensifying the frustration they already feel of telling the same story to everyone who comes through the door.

Second, I was clear that AQP and open tendering would be a barrier to reform. I believed then, as I still do now, that re-engineering the way services work - moving from the hospital to the home - is the big challenge that the NHS faces. I believed those changes were likely to happen more quickly if NHS organisations and employees had the stability and security to embrace changes in the way they work. Also, the amount time and bureaucracy tied up in the contracting process can delay service change.

Third, I knew that all the evidence from around the world tells us that market-based systems cost more to run than systems like the NHS.

But there was another, more simple reason. In the end, I am not neutral about who provides NHS services. I believe in the public NHS and what it represents - a service based on people not profits. That is worth protecting.

These were the principles and values I brought to the on-going process I inherited as Secretary of State in late 2009 in respect of Hinchingbrooke Hospital. This process has been initiated some time before I arrived under the then thinking about provider neutrality. When I changed policy to NHS Preferred Provider, I specifically asked for my new rules to be applied to this tender process. In addition, outside of that process (and although there was still an NHS organisation involved in it), I asked the NHS to approach directly all surrounding NHS hospitals to see if an NHS operator could be found.

That was the position I left behind when the parliament was dissolved and it was the situation which the coalition inherited. Nothing had been signed by me and the process could have been stopped at any time.

From there, 18 months later, a private operator for the hospital was appointed by coalition ministers. That is why Clegg's claims in the Commons on Wednesday were a total distortion of the facts. The fact is that the decision to appoint Circle probably crossed his desk at some point. Clegg's government privatised the operation of Hinchingbrooke. That is a fact.

I have acknowledged that the last government let the market in too far. That is why I changed the policy. But the coalition's Health and Social Care Act, which Clegg and his MPs supported to the hilt, takes things much further than anything Labour did. It gives the competition authorities a role in the NHS for the very first time. It allows NHS hospitals to earn half their income from treating private patients. And it effectively mandates open tendering of NHS services and, in so doing, places the NHS in the full glare of EU procurement and competition law. That is why I fought it tooth and nail when it was going through parliament.

What is indefensible about this is that it has happened without the public ever having had a proper chance to express a clear view about NHS privatisation. No party has ever been as clear as they should have been about the extent of their plans. So the coming Election presents an opportunity to put that right.

I am clear that, if the market is allowed to carry on advancing into the heart of the NHS, it will eventually destroy everything that is precious about it. So both I and Ed Miliband have nailed Labour's colours to the mast: we believe in the public NHS and will protect it by repealing the Coalition Act and making it our Preferred Provider. The Deputy Prime Minister, by contrast, continues to support a government policy of opening up the NHS to tendering and competition.

There is a legitimate debate to be had over the next five months about which path represents the best future for the NHS. But let's at least have an informed debate on this emotive issue on the basis of the facts rather than spurious claims at PMQs. I have tried to do that by giving this honest account of how Labour's thinking has evolved over the years and shaped the clear position we will take into the coming election. Is it too much to expect Clegg, Cameron and Farage now to do the same?

Andy Burnham is Labour MP for Leigh and shadow health secretary