British Airways flight from Tokyo to London declares emergency - report

A British Airways flight to London has declared a mid-air emergency, according to Flight Radar 24.

The BA8 flight was flying from Tokyo to London and declared a squawk 7700 - the aviation term for a general emergency - when it was approaching one of the busiest airport London Heathrow.

Boeing 777 is over the North Sea and descending towards the capital.

The flight was due to take off from Japan at 8:50 am and land in London at 1: 10 pm.

But the aircraft was delayed and did not leave Toyko until 11:18 am.

The plane has been airborne for more than 11 hours and has covered a distance of over 9,500km.

#BA8 from Tokyo to London squawking 7700 nearing London. Reason unknown at this time. https://t.co/nR65TdMyigPlease see https://t.co/Z4rbd3WWtK for more information about Squawking 7700. pic.twitter.com/YaEif5UD42

— Flightradar24 (@flightradar24) September 17, 2019

Further details are awaited.

This is a developing story.