"Jack" is a sailing term meaning flag. The flag of the UK is commonly known as the Union Jack. It has been used as the British flag since 1603 when Scotland and England were united. The original design combined the red cross of England with the white diagonal cross on a blue background of Scotland. The red diagonal cross of Ireland was added in 1801 when Ireland became part of the UK. Whales is not presented on the union jack because it is principality of England. The red dragon of Cadwallader which is now the national flag of Wales dates from 1950. The Union Jack is most often seen flying from the public buildings or at sport events. Many people feel strong loyalty to the national flags of England, Scotland, Wales or Northern Ireland. There is also a flag of the EU a circle of gold stars on a blue background. It is also seen in Britain for example on car nomber plates.