This footage appears to show a mysterious giant creature ‘swimming’ in the River Thames.
In the video a dark object seems to rise up from the murky waters momentarily before ducking back down again.
A large shadow can still be seen at the bottom of the capital’s river, metres from the landmark O2 arena in Greenwich, South East London.
The clip has been filmed by a passenger on the Emirates Air Line, which passes over the river giving skyline views of the city.
However, several people have speculated that the creature could be a lost sperm whale .
It wouldn’t be the first time a whale has appeared in the River Thames.
In 2006 a young female Northern bottlenose whale was discovered swimming in the river – and later became dubbed the River Thames whale.
It was the first time the species had been seen in the river since records began in 1913, but she sadly died during a rescue mission.
Almost 50 whales and 450 porpoises and dolphins have reportedly being spotted in the city’s waters in the years since.
Canary Wharf, close to where this mysterious creature was spotted, is the most likely spot to see large marine life according to the Zoological Society of London (ZSL).
The charity told the Evening Standard more than 2,000 seals had been spotted in the river – some as far upstream as Hampton Court.