Londoners were treated to an unusual sight as a rare cloud formation gathered over the capital.
Pictures taken in south London showed clouds likened by one social media user to a black hole.
And a wave-like formation was captured by Twitter user Iain Mellis in the centre of the capital.
The clouds were identified by experts as Asperitas, a rare formation which was only recently given a name.
According to the Met Office: “Asperitas is a distinctive but relatively rare cloud formation that takes the appearance of rippling waves.
“These wave-like structures form on the underside of the cloud to make it look like a rough sea surface when viewed from below.”
Exactly how the clouds are formed is not known, but they require unstable atmospheric conditions and are sometimes associated with the aftermath of thunderstorms.
Asperitas was officially recognised by the World Meteorological Organisation in 2015.