Image caption Cantona wants a 'real revolution'

Former footballer Eric Cantona has called on a new form of direct protest - a mass cash withdrawal - to bring down the banks. So what would happen if everyone tried to withdraw their savings?

From the footballer who once kung-fu kicked an abusive fan, a new form of direct action without any violence.

Take your money out of the banks and spark their collapse, says Eric Cantona, in advice to the students and public sector workers holding protests in France and the UK.

"We must go to the bank. In this case there would be a real revolution," says the French former Manchester United star in a newspaper interview that has been filmed and widely viewed on YouTube.

"It's not complicated. Instead of going on the streets and driving kilometres by car you simply go to the bank in your country and withdraw your money, and if there are a lot of people withdrawing their money the system collapses. No weapons, no blood, or anything like that."

So how effective would this form of protest be?

In the very unlikely circumstance of everyone heeding Cantona's call, there are obvious practical hurdles preventing that number of people getting to cashpoints or queueing up in branches to withdraw their savings.

The Answer No, but it could lead to a rationing of withdrawals or branches closing

Depositors would not have a crisis of confidence so it would not resemble a conventional 'run' on the bank

But setting those aside, the banks would need to find more cash, because only about 5-10% of people's savings are kept in banks' tills. The rest is lent out or invested.

"Banks only keep a small fraction of their deposits as cash, so the cash machines would run out and cash in the branches would run out," says Richard Wellings, deputy editorial director of the Institute of Economic Affairs.

"They could go to the Bank of England [for some cash] or they could sell assets to release cash but they probably wouldn't bother because it would just be a temporary blip."

The only effect it would have is to inconvenience a lot of people when they go to the cash machine Richard Wellings, Institute of Economic Affairs

Although some branches may have to close, it would be very different from a conventional run on a bank because depositors would know it was related to a protest and not an underlying problem with the bank, so confidence would not be hit in the same way, says Mr Wellings.

Furthermore, all deposits up to £50,000 are government-guaranteed, through the protection of the Financial Services Compensation Scheme, so that would help strengthen confidence and prevent a panic.

All their digital transfers would carry on as normal, this would just affect the physical payments of cash. These could be rationed or temporarily halted.

"The only effect it would have is to inconvenience a lot of people when they go to the cash machine and try to withdraw their money but find there's no cash there. But it would not cause the collapse of the banking system. Notwithstanding the big problems, I can't see it having much of an effect in reality."

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When there is a run on a single bank for reasons of confidence, then the government can step in, as it did for Northern Rock in 2007.

But if there was ever a collective panic sparked by a mass withdrawal against all the banks, then the consequences are far more serious.

In 2001 during the Argentinian economic crisis, large numbers of people began taking their cash out of the banks, so all bank accounts were frozen for months.