ORDER a map of the far west of Cornwall from the Ordnance Survey and, at least for a while, it will be different from any other map in the UK.
For the very first time in hundreds of years, magnetic North is starting to move east of grid north – and the area of mainland Britain which is the first to be affected is west Cornwall.
The magnetic North Pole of the Earth currently lies in the Arctic Ocean, west of Ellesmere Island, to the north of mainland Canada.
But the pole moves around 25 miles a year and in the past 150 years, the pole has wandered around 685 miles in a roughly northerly direction, meaning constant adjustments have to be made if using a compass.
Gemma Nelson, from Ordnance Survey, said: "The magnetic variation throughout Great Britain has been a few degrees west of grid North with the amount of variation changing every year.
"For years the number has decreased, and now in the far south west of Britain, the north on your compass lies to the east of the north on your map for the first time since before the Ordnance Survey came into existence in 1791.
"This is currently only affecting people west of Penzance and the new magnetic variation will be shown on any of our custom-made maps centred in that area.
"Magnetic North is currently moving around 30km every six months, so for example, it will take four or five years to make it over to the Ordnance Survey office in Southampton."