There are three norths: true north, magnetic north and grid north. According to www.ordnancesurvey.co.uk, the three norths are defined as follows: Grid North: the direction of a grid line which is parallel to the central meridian on the National Grid. True North: the direction of a meridian of longitude which converges on the North Pole. Magnetic North: the direction indicated by a magnetic compass. Magnetic North moves slowly with a variable rate and currently is west of Grid North in Great Britain.