A swarm of flying ants moving across the South East is so big it has been spotted from space.

The giant cloud of insects was picked up by forecasters from the Met Office off the coast and was initially mistaken for rain.

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A video was released by the Met Office yesterday, alongside a tweet saying: "It's not raining in London, Kent or Sussex, but our radar says otherwise... The radar is actually picking up a swarm of #flyingants across the South East."

"During the summer ants can take to the skies in a mass emergence usually on warm, humid and windless days #flyingantday."

A spokesman for the weather service said there are likely 'thousands' of ants within the swarm.

He said: “It’s not unusual for larger swarms to be picked up.

“A similar thing happened almost exactly a year ago on flying ant day.

“On days like today, when it is sunny, the radar detects the swam but we are able to see they are not the same shape as water droplets, and in fact look more insect-like.”

What is flying ant day? 

Flying ants often seem to appear on the same day in different locations in the UK – flying ant day.

According to the Royal Society for Biology website, the swarms are caused when males and new queens leave the nest to mate, with many ant colonies doing so on the same day when the conditions are just right.

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It said: "However, our citizen science project, the Flying Ant Survey, has found that there is not actually one day where these ants all appear all at once, but that, depending on weather conditions, the ants can start emerging and flying at almost any point during the summer months, and won't all necessarily appear only on one day either."

The RSB added: "Our survey found that there is often not just one flying ant day but on as many as 96 per cent of days between the start of June and the start of September flying ants are spotted."