HOW many?

I once heard, on the radio, a claim that something like 25% of the "old" £1 coins in circulations. Immediate reaction - WHAT?!?!?!? 
So I decided to have a look around.
"Brits have about £1.3 billion worth of coins stored in money boxes around the country, but how do you know if you’ve got a fake?
It was estimated that as many as 3 per cent of the old round pounds were fake, representing £50 million of fake coinage in circulation in the UK." 
Which seems like, maybe, a more realistic figure. Either way, in our 13 years in the shop I don't think we experienced more obvious fakes than could be counted on one hand. I spotted this some time ago; it has vastly "improved worserer" since it came into my clutches. I once weighed a couple of coins and was amazed to find (Can no longer check unfortunately.) that the forgery was actually lighter than the genuine article.
I found a use for this one ... It makes a perfectly viable "Supermarket Trolley" token.