The City of London Police and the London Metropolitan Police

The city of London police is not the same thing as the London Metropolitan Police. The force was organized by Robert Peel in 1829, but Peel had left the center of the city out of his new force. It used Peel's model to organize the force, but kept it entirely separate. Someone set on committing a crime could carry out their plan, and then slip from jurisdiction of one force into the territory of another.