If you're travelling to the UK in the near future, you'll want to become acquainted with the currency. Below is a quick guide the coinage you'll be using. All UK coins currently have a cameo portrait of Queen Elizabeth II on one side.
£2 piece: This coin is larger than the others, and heavier, sporting both gold and silver metals. The edge is inscribed with the quote "Standing on the Shoulders of Giants," by Sir Issac Newton, and the inner silver coin has varying themes.
£1: This coin is small, heavy and gold coloured. It will be inscribed with one of three country crests (Three lions for England, a thistle for Scotland, and a leek for Wales).
50p, or 50 pence, is worth 1/2 of £1. It is a large coin with flat edges, featuring Britannia sitting astride a lion, and is entirely silver in colour.
20p, or 20 pence, is a small coin with flat edges, silver in colour and inscribed with the Tudor Rose (the rose is the national flower of England). It is worth 1/5 of £1.
10p, or 10 pence, is a large, silver coin with rounded edges, featuring a lion wearing the royal crown. It is worth 1/10 of £1, and is similar in size and shape to a US Quarter coin.
5p, or 5 pence, is a very small coin, silver in colour, featuring a thistle (the symbol of Scotland). It is worth 1/20 of £1.
2p, or a Tuppence/Tupenny, is a large, copper coin featuring the Prince of Wales feathers. It is worth 1/50 of £1.
1p or one penny is similar in size and appearance to a US penny (small and copper). It pictures the portcullis of Westminster Palace and is worth 1/100 of £1.
All UK coins feature the number of their worth somewhere on the face of the coin.