It will be the first time the prime meridian of longitude - zero degrees east and west - has been specially shown on Britain's principal maps and will, the Ordnance Survey says, allow people to celebrate the precise places where time changes at midnight on 31 December 1999 at any point along the line.
The decision is announced today - exactly one year from Millennium Eve. Seventeen maps in the highly detailed new "Explorer" series will track the line through towns and villages across the countryside.
It runs north from the Channel coast at Peacehaven, shaving Lewes and East Grinstead in Sussex before heading through the suburbs of south London to the Royal Observatory at Greenwich, where the meridian was first calculated in 1851.
A brass line at the site marks the division between the eastern and western hemispheres and is a popular place for people to be photographed with one foot in each. It is also the new millennium's official Greenwich Mean Time starting point.
The meridian continues north through Leyton and Walthamstow in north- east London to Waltham Abbey in Essex. Then it passes the eastern edge of Royston in Hertfordshire and the western side of Cambridge before crossing the Fens and running up through Lincolnshire, just missing Boston and Louth.
It crosses the Humber estuary and the Holderness peninsula before heading out into the North Sea and up to the North Pole, touching no more land.
The new, highly detailed maps are at the scale of 1:25,000 (4cm to 1km or 2.5in to the mile) and will cost pounds 5.50. The first, of the Greenwich and Gravesend area, will go on sale next month and the rest will be published in stages by the summer. They will show the meridian as a green line.
"As the new millennium nears, we've had many requests to track the route of the time line on our maps," said Paul Franklin, Ordnance Survey's publishing manager. "That's because many people want to know whether their village, street or even school is on or near the line so they can arrange special celebrations both in the build-up to the millennium and on the big night itself."
Only six other countries besides England are host to the Greenwich meridian. It runs down through France and eastern Spain, across the Mediterranean and then through four nations in Africa - Algeria, Mali, Upper Volta and Ghana - before heading to the South Pole.Reuse content