It's intriguing and slightly baffling why David Cameron has felt impelled to make another speech about the NHS.

Yes, health has become a serious political problem for the coalition. Andrew Lansley's radical plans for reorganising the NHS in England – or, rather, the unpopularity of key elements of them among health professionals and unease among the wider public – have given the prime minister and, separately, Nick Clegg, a real test of political skill.

But there is already a government "listening exercise" under way and a review being undertaken by an independent team of 44 experts, led by Professor Steve Field. So why didn't Cameron wait for that taskforce to produce its report by 1 June and reveal his thoughts then?

In fact, there are several different but related processes under way. The Field-led one is important. But Downing Street is also seeking its own, more direct help on the likely shape of "the reforms of the reforms" from a recently-assembled "kitchen cabinet" of eight health experts who are all either determined pro-NHS reformers, or old NHS hands who know how much change it is possible to force on the nation's favourite institution – or both.

The PM's speech at Ealing hospital bears the hallmarks of the clear thinking of some of those people, such as the Nuffield Trust director Dr Jennifer Dixon and the cancer expert (and Labour turned Tory health adviser) Professor David Kerr.

Clegg, for his part, is under serious pressure from within his own party, especially from Shirley Williams. Meanwhile, associates of Lansley, the health secretary – mentioned just once in Cameron's speech, towards the end – say that privately, and almost uniquely, he still thinks his bill needs only the odd tweak here and there..

The speech seems significant in several ways. It boldly and unashamedly explains why the NHS does have to undergo major reform if it is to cope with the growing pressure of an ageing population, rising numbers with long-term conditions such as cancer and diabetes, and the desire to give patients access to new treatments and technologies.

Few would disagree with Cameron's diagnosis of the big, long-term challenges – no one credible pretends that the status quo is an option. So his words are in line with what both he and Lansley have been saying for months.

But, crucially, the speech does seem to confirm that, once Plan B on the health bill emerges – probably later next month – it will be significantly different to the masterplan that Lansley has championed for 10 months.

In his interview with the Guardian last Saturday, Field shot the competition fox that has got the medical establishment so worried. Field rejected Lansley's future vision of hospitals having to compete with each other in a heavily marketised NHS and said that the duty of the regulator Monitor should instead be to promote co-operation and collaboration and better integration of health services – an approach much better suited to the needs of individual patients' needs, he stressed.

Cameron's line that "there will be choice for patients, not competition for its own sake" is telling, and in spirit very in tune with Field's pragmatic, non-ideological but still pro-reform views.

And – usefully, given that Plan B will have to command doctors' consent – it will probably be a big help in assuaging the fears of the British Medical Association, the medics' union.

The PM has basically said NHS reforms will not go ahead unless health professionals are broadly happy with them. "Change – if it is to endure, if it is to really work – should have the support of people who work in our NHS. We have to take our nurses and doctors with us ... we want to work with them, not against them," he said.

And there was this: "I agree we need hospital doctors and nurses to be much more closely engaged in commissioning" – something the bill makes no provision for.

He also pledged "substantive changes to improve the reforms, based on what we hear". And, probably most significantly of all: "This government will never, ever take risks with the NHS".

The Lansley proposals are nothing if not risky, as influential organisations such as the King's Fund and NHS Confederation have repeatedly pointed out.

So where is the NHS reform process after Ealing? Guided by the same diagnosis of the service's problems but heading towards a different form of treatment to that envisaged by Lansley.

A broad consensus on what Plan B might well will look like is emerging from Field's comments, the health select committee chairman, Stephen Dorrell, the Lib Dems' "red lines" on key issues and now Cameron's latest speech.

It will still be a radical plan from a government that thinks the NHS is as important a priority as the budget deficit, welfare reform and education. It just won't be the plan that Lansley – and, until recently, Cameron too – have been trying in vain to sell since last summer. Get ready for Plan B.