Signage changes were made at night
Stansted Airport in Essex has renamed its 3,000m (9,750ft) runway because the position of the Earth's magnetic North Pole has moved.
The runway was known by pilots and air traffic controllers as 23/05 because of its location and compass heading.
The magnetic North Pole drifts naturally, and every 50 years its position alters significantly.
Managers at Stansted decided they must call the runway 22/04 to reflect the new position and bearing.
Trevor Waldock, head of airside operations, said: "We've had to make this change due to the Magnetic North Pole slowly drifting on the Earth's surface but our runway remains in a fixed position.
"It'll roughly be another 56 years before we have to consider changing it again.
"Redesignating the runway at a busy international airport, such as Stansted, presents a number of complex challenges, so we've had a programme of works specially organised to minimise any disruption to normal operations."
The project, which took place at night, was completed on 5 July and included the replacement of all airfield signage and the repainting of the huge numbers at each end of the runway.
The magnetic North Pole will continue to drift until it eventually switches with the magnetic South Pole.
The Earth last went through this an estimated 780,000 years ago.
With time, due to the Magnetic North Pole moving south, the Northern Lights will be more regularly visible in the UK.