Wednesday 2 November 2022 12:13 AM True north, magnetic north and grid north to combine over Britain for the first ... trends now
The three 'norths' are due to combine over Britain this month for the first time in history, and will stay over the country for the next three-and-a-half years.
What this means is that true north, magnetic north and grid north will all line up, according to national mapping service Ordnance Survey.
True north is the direction along the surface of the Earth that ends at the North Pole, while magnetic north points where the planet's magnetic field goes downwards.
Grid north is the direction of the grid lines on maps, that usually point towards or near the North Pole.
The three norths will make landfall at the village of Langton Matravers just west of Swanage in early November, before slowly travelling up the country.
Dr Susan Macmillan, of the British Geological Survey, said: 'This is a once in a lifetime occurrence.
'Due to the unpredictability of the magnetic field on long timescales it's not possible to say when the alignment of the three norths will happen again.'
The red line shows magnetic north, while the blue ‘special line’ is true north and the grid north line which are perfectly aligned. The three norths will first make landfall at the village of Langton Matravers just west of Swanage (pictured) in early November. Magnetic north will move eastwards over time
True north is the direction along the surface of the Earth that ends at the North Pole, while magnetic north points where the planet's magnetic field goes downwards. Grid north is the direction of the grid lines on maps, that usually point towards or near the North Pole
At some point this week, the triple alignment will cross through Langton Matravers before moving northwards to Poole by Christmas and then further up the country
Mark Greaves, Earth Measurement Expert at Ordnance Survey, said: 'It is no exaggeration to say that this is a one-off event that has never happened before.
'Magnetic north moves slowly so it is likely going to be several hundred years before this alignment comes around again.
'This triple alignment is an interesting quirk of our national mapping and the natural geophysical processes that drive the changing magnetic field.'
Grid north is represented on Ordnance Survey maps by the vertical blue grid lines, and has been since the current mapping system was introduced in 1936.
Across most of the maps, true north bends away from grid north since the former reflects the
