What does the cross on british flag stand for?

The Union Jack does not have a single meaning for the red cross on it. Instead, the cross represents three patron saints across various countries of the United Kingdom.

- The white diagonal cross on a blue background in the upper left part of the flag is the Cross of St. Andrew, Scotland's patron saint.

- The white diagonal red cross on a white background in the upper right part of the flag is the Cross of St. Patrick, Ireland's patron saint.

- The red cross on a white background that's centered in the flag is the Cross of St. George, England's patron saint.