Substitute Cash In A Cashless Society

There is currently a series of articles on the BBC news about a possible future of a cashless Britain. If that eventually happens, I can forsee private companies stepping into the vacuum supplying cash substitutes. My thoughts are as follows.

There are precedents for people wanting and supplying their own forms of cash, outside the official system. Britain has a rich history of private tokens. In prisons cigarettes have often become the cash substitute. People have used phone tokens and petrol vouchers as cash. No doubt forum members can think of other examples worldwide.

Suppose I set myself up as a private cash supplier. People could then buy the cashtokens from me, for a fee of course! ( to cover cost of manufacture/supply, as well as covering my desire to enrich myself at the expense of others ). These cashtokens could then circulate at face value, or for whatever discount people wanted to put on them. I could offer a buy-back service to credit a bank acount, for another fee of course, as a sop to maintaining the cashtoken credibility!

The cashtokens could be paper or coin based like cash now, or could be plastic like the Tranistrian "coins" released a little while ago, or something else durable and hopefully difficult to forge.

Us coin collectors would lose one avenue for collecting, but would gain another.

What do forum members think? Is this a realistic possibility? How would government safeguard such practices? Would they just let people get on with it, happy in the knowledge that they had privatised cash by the back door?