Kew is an Observatory in the UK established by King George III in 1769 to monitor the transit of Venus. Later chronometer trials were established and recorded. All the famous makers submitted their chronometers for testing and a league table was published yearly, a very competitive affair. The purpose was to establish makers as fit for purpose to supplying marine chronometers to the military ships of the realm. Makers from abroad were welcomed. London time was established here before GMT.