Prime minister Tony Blair has warned against creating an independent NHS, saying it would stymie decision-making and be in danger of being hampered by the demands of special interest groups.

Speaking at a King's Fund debate on Monday, in what will almost certainly be his final speech on health as prime minister, he argued that the major elements of the last 10 years of reform would outlast future governments, while also conceding mistakes over the creation of primary care trusts.

Mr Blair said he was wary of calls to create an independent NHS board, saying: 'If it is a way of making decisions, I can understand the point of it. My worry is if it became a means of avoiding decisions.

'In the end someone has got to take the decision if it is a driving force for change, rather than a brake on it. It all depends what its purpose is - is it there to take tough decisions?'

Mr Blair returned again and again to the point that an NHS based on choice, plurality and competition would not be dismantled by his successors. 'I personally think that a less monolithic NHS with more competition, with practice-based commissioning and payment by results will stay in place. I can't see the basic framework being changed. I can't see any government turning their back on that.' He also indicated that social care could benefit from the same dose of competition and choice as healthcare has done.

'In the first two years we didn't push forward fast enough [on introducing reforms],' he admitted. However he defended the decision to increase NHS funding in advance of those reforms bedding in: 'I have always thought that dealing with reform before under-investment was addressed would be difficult.'

After criticism of continual reorganisations by speakers, including Royal College of Nursing.general secretary Peter Carter, Mr Blair conceded that 'fair points can be made about reorganisation'.

'There was a lot of support for primary care groups at the time and in terms of where we were at the time, it made sense to move to a system [of 303 primary care trusts]. It seemed like a good thing to do. In retrospect it would have better to avoid it but at the time it was difficult to foresee.'

He defended charges that reforms had lost the faith of NHS staff, arguing that like Margaret Thatcher's reorganisation of industry in the 1980s, 'while the change is being gone through it extremely difficult. People make a more rational assessment at the end. We have to hold our nerve while dealing with those points that are reasonable.'