A geological phenomenon has led to the 3,000-metre runway at London Stansted Airport to be renamed.
Small changes in the position of the Earth's magnetic field has meant that the runway's former title of 23/05 - based on its location and compass reading - has changed to 22/04.
Trevor Waldcock, head of airside operations at London Stansted, said: "We've had to make this change due to the Magnetic North Pole slowly drifting on the Earth's surface while our runway remains in a fixed position. It'll be roughly 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 work specially organised to minimise any disruption to normal operations.
"I would like to thank all those staff who have worked tirelessly over the past few months to successfully deliver this challenging project at one of the busiest single-runway airports in the world."
The Magnetic North Pole will continue to drift until eventually switching with the Magnetic South Pole. It is estimated that the Earth last went through this shift approximately 780,000 years ago.
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