The office of high sheriff, as the monarch's representative in a county, is over 1,000 years old, with its establishment before the Norman Conquest. The office of high sheriff remained first in precedence in each county until the reign of Edward VII when an Order in Council in 1908 gave the lord-lieutenant the prime office under the Crown as the sovereign's personal representative. The high sheriff remains the sovereign's representative in the county for all matters relating to the judiciary and the maintenance of law and order.
The office of High Sheriff of Greater London was created in 1965 and covers the ceremonial county of Greater London. It does not cover the City of London, which has its own two sheriffs. It replaced the offices of High Sheriff of the County of London and High Sheriff of Middlesex which were abolished in 1965.