Traditionally, all distances from London are measured from a statue of which English King?

The equestrian statue of Charles I at Charing Cross, London, is a work by the French sculptor Hubert Le Sueur, probably cast in 1633.

Its location at Charing Cross is on the former site of the most elaborate of the Eleanor crosses erected by Edward I, which had stood for three and a half centuries until 1647. Charing Cross is used to define the centre of London and a plaque by the statue indicates that road signage distances are measured from this point. The statue faces down Whitehall towards Charles I's place of execution at Banqueting House.

On the pavement a few feet behind an equestrian statue of Charles I that sits on a traffic island just south of Trafalgar Square, there is a plaque:

On the site now occupied by the statue of King Charles was erected the original Queen Eleanor's Cross, a replica of whch stands in front of Charing Cross station. Mileages from London are measured from the site of the original cross.