A 'Blue Peter' flag is a blue flag with white center to signal that a ship is ready to sail.
By raising the blue peter flag
The BLUE PETER. A white flag with a blue rectangle in the centre.
Blue Peter
The Canadian flag is white with a red maple leaf in the centre
Blue Peter, a childrens show named after the flag that is raised when a ship leaves a harbor, was created with a 180 pound budget and ideas from the kids that watched the show.
Apparently origin of the Russian flag to czar Peter the Great. Peter had ordered a Dutch-built frigate from Amsterdam. The frigate had red-white-and-blue, Peter decided to model Russia's naval flag after by changing the sequence of colors. Carel Allard book describes a similar flag design noted as belonging to czar of Muscovy.
In the UK the BBC program is Blue Peter
There is no blue on the English flag
The bavarian flag is white and blue
The Canadian flag does not have anything blue.
The Bonnie Blue Flag was created in 1861.