From Wikipedia:
The history of money spans thousands of years.
Many items have been used as commodity money such as naturally scarce precious metals, cowry shells, barley, beads etc., as well as many other things that are thought of as having value. Modern money (and most ancient money) is essentially a token - in other words, an abstraction. Paper currency is perhaps the most common type of physical money today. However, objects of gold or silver present many of money's essential properties. [1]
If you print money it is a crime. You go before a beak (magistrate) and get sent down.

When the Bank of England prints billions of pounds during this crisis of 2007 to 2012, it is called "quantitative easing".
(See Quantitative GREASING if you want to know about future inflation).

Spot the difference?

In case of too many duff £ 50 notes, people get anxious and stick to 20s. When the Bank prints billions, foreigners who have brains swap these Pounds for something else like gold or euros or Aussie dollars. They don't want our 20s, or 50s (or even 100s if the Bank created them).

When some months later you have saved enough for Corfu, you find yourself a bit short. The pound has dropped and a Greek beer costs £ 2 instead of £ 1.60.

£ 200 billions of new pounds have been printed to keep the banks open. Banks trade debts with each other like house loans. You would be miles better off if house prices halved, but oldies want their house prices to rise for ever. They grumble about higher prices of everything, but you really suffer on Corfu. The oldies laugh and tell you that when they were students, a beer cost 10p. They go quiet when you point out that you have seen a 1964 advert for a house in Clapham Manor Street for £ 2,500. The pound should be divided by 100 to return its value. Then a Greek beer would be only 20p again. This shuts them up as they try to work out whether their 45 year inflation scam was about to be reversed.

Several more percipient FT economists proposed a more honest solution than printing more £ British:
"Let each British bank sort out their toxic loans by offering them openly for sale".
Let's be blunt. All money is needed for, throughout history until the world went mad about 'credit' (only around the time we were born) is (a) a store of wealth and (b) a means of exchange of goods. As a store of wealth, gold served us pretty well for thousands of years - but it is bulky as well as attractive in its own right. As a means of exchange, we now have computers and clever accountants - too clever, but not wise!
Above all, we now have bad-economists, who abuse our whole money system.