Paul Barnes is Campaign Director of Conservatives Abroad. He lives in the South of France.

As thousands  of people marched through London recently demanding that the Government spends more money on the NHS, something remarkable was happening just across the Channel.

Despite the flu epidemic here in France being twelve times worse than in the UK, the state-run hospital in Calais had so much spare capacity that it was offering to treat patients from Dover whose operations had been cancelled because of the annual NHS winter crisis. When I first moved to France and visited my new GP, he said I needed to go to hospital for some tests.  As he phoned the hospital,  I took out my diary to see what I was doing three to six months ahead.  “Ok” he said, “I’ve booked you in for one o’clock this afternoon”

“But isn’t there a waiting list?” I asked.  He was mystified. “What’s a waiting list?” he replied. “Why on earth should anyone have to wait to go to hospital?”

How can it be that two such similar countries have state health services with such a massive difference in capacity?  What are the French doing right that we are doing wrong?

A plausible answer is the extra amount of money that the French spend on their health service.  France spends around 12 per cent of GDP on the state health servuce, compared with the UK’s eight per cent of GDP.  But when you look into it, it’s more subtle than that.  The Office of National Statistics shows that the two governments actually spend about the same amount (Britain just under that eight per cent, France just over it.)

The big difference is in the non-state contributions made by individuals to their health care –  both the amount spent and, more importantly, where it is spent.  The key to this is the different charging system operated by each state health service.  In the UK, everyone gets 100 per cent  of their treatment costs paid by the state – even millionaires and others who could afford to pay a bit towards it.  That’s the bedrock of the NHS system.

In France, the state pays 100 per cent of treatment costs for all those who can’t afford to pay – children , the elderly, the unemployed and low wage earners.  For all others who are earning or wealthy, the state pays the major proportion of their treatment costs, anything from 70 per cent depending in the treatment and the individual’s financial status. But each person makes up the rest.

These people can then, if they wish, take out health insurance to cover the rest.  Most do.  Mine cost around €100 per month, less than my car insurance.

Here’s the difference this system makes.  In the UK fewer people take out health insurance – after all, you don’t need it if the state is paying 100 per cent of your treatment costs. More importantly, any additional contributions from personal health insurance is not spent on the NHS; it is spent on private treatment to avoid long waits for NHS treatment.

In France, the top-up system means that more people take out insurance, and it is mostly spent in the state health service, not private treatment.  You don’t need to go private when there are no waiting lists.

The difference that makes to the state health service budget is enormous. The Nuffied Trust estimates that if the UK expenditure on the state health service (combined state and personal) was the same as in France it would add a staggering £24 billion a year to the £116 billion NHS budget.  That’s a 20 per cent annual increase, dwarfing the amounts demanded by Saturday’s marchers and far more than £350 million a week promised on the side of the Brexit bus.  And all done with no tax increase and no hypothication.

Labour’s last NHS spending spree, which contributed to massive and unsustainable annual deficits because not even Gordon Brown’s tax increases were enough to fund it, shows that a modern health service cannot rely on just tax financing.

So why don’t we do this? I think the main reason is that our quasi-religious obsession with the NHS being free at the point of delivery is the key block to this mixed-funding system, used by so many successful continental health systems.  Which means that, ironically, those marchers are the key blockers of a reform that would give them far more than they are asking for. And the 2017 election response to social care proposals suggesting modest contributions from those who can afford it make this too risky a policy to propose.

So NHS winter crises will continue, patients will continue to lie on trolleys in corridors for hours, operations will continue to be cancelled and waiting lists will continue to get longer.  While in France we will still be wondering what to do with all that spare hospital capacity.