People, please be careful, unscrupulous sellers are taking many people for a ride selling 20p coins with 'No date on the Queens side' or words to that effect. Yes if you have an original (no date on EITHER side) they are worth about £50.00 (July 2009). Be sure to enquire if there is ANY date on the coin. If it has a date it's worth... 20p. Here's what the mint has to say about it;
"The problem occurred after all the coins from the 1p through to the £1 were redesigned last year. The change of the 20p design meant moving the year date from the tails side to the side with the Queen's head. However, thousands of coins were minted using the old version of the Queen's head, which does not have the year date, and the new version of the tails side, which also does not have a date."
The first one was allegedly sold for £5000+ here on ebaY, but considering that there are more than 300,000 of the coins in existance their real value is falling all the time. In short if you want a quick way to double your money.... fold it in half and put it back in your pocket.
So there you have it! :O)
Take care out there... Caveat emptor!