A million people in the UK have petitioned Downing Street against polyclinics – the 'super-surgeries' that will absorb or replace many existing family doctor practices – the so-called general practitioners or GPs.That's almost as many who petitioned against road congestion charging. Given that they are both so unpopular, can we conclude that these ideas are both pretty daft?

Well, road charging is a sensible idea. It allows you to charge on the basis of use, and on the basis of the costs that road users cause to others when they all decide to come into town at the busiest times. People reject it because they know politicians too well: they fear it will be an extra charge, not one which replaces existing motoring taxes.

Polyclinics aren't a bad idea either. There's strong evidence that indiividual GP surgeries have poorer medical outcomes than group practices, where doctors can share administrative and nursing backup, can share patient loads, and can specialize to a certain extent. Making them even bigger, allowing diagnostics and even some surgical procedures to be done at the same site – saving patients from going back and forth to hospital – seems an obvious extension of this.

But now patients are saying they rather like their local GPs. They like to see the same doctor every time. They like the fact that their doctor is near to where they live. And NHS experts too worry that they are just going to duplicate what hospitals already do.

Again, it's the fact that the existing setup is state-run. That means there is no market information to tell the provider (the government) what people actually want. I suspect that in a market healthcare system, people would rather like small-scale medical services near where they live. Or maybe better, something near their work that was open on their way in and out, and at lunchtime. And probably they would like smaller (dare one say 'cottage') hospitals or clinics near where they live, in preference to the huge district hospitals that 1970s state giantism gave us. And they'd like more downline tests, consultations and monitoring, rather than having to turn up in person all the time.

But that's only a guess. Without the preference information that we get from having a market, we can't know. Which means that whatever the government does, it's bound to get wrong, and upset a lot of people in the process.