The French are revolting again. This time it is over the location of the Prime Meridian - the line of longitude from which all time zones are referenced.

France is to mark out "Le Meridien" with trees and olive groves and a mass picnic, joining the 337 towns and villages over a distance of 960 kilometres.

Paris: Forced to give up its claim

This is not the line that runs through South East London in the UK, but the French version that lies just over two degrees east of Greenwich and nine minutes and 22 seconds ahead of it.

To suggest, however, that Paris might usurp Greenwich's supremacy is ridiculous. Paris ceased to be a prime meridian candidate following a centuries-long tussle.

The deathblow for the French meridian was delivered in 1884 in Washington, USA, when an international conference recognised Greenwich as the centre of time.

In retrospect, it was the only decision that could have been made. The vast majority of mapmakers and sailors were already using the Greenwich meridian as their reference. Only Brazil and Santo Domingo backed the French claim.

Beating the British

For a while, France stuck to its line. But eventually, the disparity became impossible to support and France was forced to recognise world opinion. Not that French pride should feel all that wounded. They did trounce the British when it came to devising an international system of weights and measures.

Greenwich: The centre of time

It was the French who proposed the very sensible metric system over the clumsy and absurd British system of chains, furlongs and miles.

The French also captured the very definition of the metre. In the days before atomic precision, the unit was originally defined as one ten-millionth of the distance from the equator to the North Pole along a meridian passing through Dunkirk and Barcelona, and, hence, also passing very close to Paris.

So Greenwich won time and Paris won distance. Entente cordial? Almost. In what might be regarded as a piece of one-upmanship, the long line of trees to be planted across France will ensure the Gallic meridian is visible from space.