"How is Lansley getting away with it?" I was asked recently by a senior NHS manager. Given that the NHS bill looks likely to make the statute book in the teeth of well-nigh universal opposition, it's an interesting question. Part of the answer lies in the policy rhetoric – an attractive world of shared decision-making ("no decision about me without me", said the white paper), with the cosy and familiar GP's surgery said to be "the new headquarters of the NHS". Who could possibly object?'

Opening up public services to greater patient engagement is indeed a desirable objective, but the crucial (and little debated) issue is how this is undertaken. The bill's decentralised model of professional-patient interaction seems to offer a palace of varieties – better sources of information for patients, listening to the patients' experience via Patient Reported Outcome Measures, recognition of the "expert patient" in the case of many long-term conditions, the roll-out of personal health budgets and – most important – the prioritisation of patient choice in the "any qualified provider" (AQP) model. It is not an agenda without virtue, but does it tell the full story?

There are other ways of increasing the stake of the public in decision-making. The most recognised route is through some form of representative democracy, and here again the government trumpets the virtue of its proposed changes – the 2010 consultation paper on democratic legitimacy, for example, boasted that "for the first time in 40 years there will be real democratic accountability and legitimacy in the NHS".

There seems to be much on offer in this respect, too, but closer scrutiny suggests a flawed approach: health and wellbeing boards will have few formal powers and could degenerate into talking shops; clinical commissioning groups have little transparency and only vague obligations; foundation trusts in the future will be accountable only to feeble governing bodies elected by a small membership; and the new Local HealthWatch organisations will be weak and underfunded. Meanwhile the really big beasts – the NHS Commissioning Board and Monitor – will hold huge sway over local decision-making, yet be totally unaccountable to localities. Individual citizens wishing to help shape their local health services will not find it easy to gain leverage in this world.

The limitations of the "individual co-production" and "representative democracy" proposals should alert us to the real agenda for opening up the NHS – increasing diversity of supply. Although there is much rhetoric in official documents about the importance of social enterprise models and the role of the third sector, it is clear that the main alternative supply will come from the private sector. NHS staff are rightly suspicious of the denuded version of social enterprise being offered to them, consisting of guaranteed short-term contracts followed by competitive tendering against larger and better-equipped private providers. Meanwhile, the AQP agenda privileges patient choice above any other considerations (such as equity, quality and continuity) and makes the unlikely assumption that patients will readily assume the role of rational consumers. Transparency and accountability simply do not figure in this model.

There is a further model that could form the basis for genuine citizen engagement with healthcare, but it has no evident place in the government's reforms – "co-production" or "participatory governance". The essence of this model is the support of communities and groups, as opposed to control by either the market or the state – an active partnership between citizen and state.

For this to work, healthcare organisations, local councils and professionals would have to engineer a paradigm shift in their approach to providing healthcare. Healthcare communities will need to be fully acknowledged as "co-producers", and their knowledge accorded a proper priority alongside the "privileged" knowledge of professionals, officials and elected members. Barriers relating to culture, language, organisational structures, management and inadequate information would all have to be tackled.

None of this would be easy – no private providers ready and waiting to pounce and organise, no representative institutions happy to readily assume more powers and responsibilities. However, the essence of the 1946 NHS Act is that certain social institutions must be maintained and enhanced for individual and collective benefit. The model emphasises social solidarity and mutual dependence for mutual benefit. Co-production embodies precisely these sentiments, yet the NHS bill will shift us towards a completely different model. In 10 years' time the NHS will be totally unrecognisable – and Andrew Lansley will indeed have "got away with it".

• Bob Hudson is a professor in the School of Applied Social Sciences, Durham University