What Flag with red x a blue background?

Here are some additional details about the flag:

- It is commonly known as the Saltire or the Saint Andrew's Cross.

- The flag features a white saltire, which is a diagonal cross, on a blue background.

- The saltire is believed to have been used as a symbol of Scotland since the 12th century.

- The flag of Scotland is often displayed alongside the Union Jack, which is the national flag of the United Kingdom.