The cloud that appeared earlier this evening
© Chris GordonThe cloud that appeared earlier this evening
People across Leicester were left astounded this afternoon when an unusual cloud formation appeared in the sky.

The formation, which looked like a rainbow around an oval of bright light, appeared at about 5pm in an otherwise murky, grey sky.

Witnesses took photos of the phenomenon and uploaded them to Twitter, many commenting on the "beautiful" appearance.

Leicester Mercury weatherman Dave Mutton said the formation was the result of a cold front moving from the North down to the South.

Rainbow cloud
© Kaz Canning

He said that when a cold front meets a warmer front, bits of cloud break off, creating a gap in cloud cover.

Today's 'gap' occurred just as the sun was setting behind it, creating the ethereal oval of light.

He said the rainbow effect appeared because of the light refracting through ice crystals or water droplets in the clouds.

Dave said: "It would have been quite a sight with the sun setting behind it."

However, Dave said it could have also been a polar stratospheric cloud.

Rainbow cloud
© Vikky Ball - General
Polar stratospheric clouds form at very high altitudes, between 15km and 25km (about 50,000 to 80,000 feet) and at very cold temperatures (around -78 deg C).

They are also known as nacreous clouds, from nacre, or mother of pearl, due to their iridescent nature.

Lisa Tubby, of Thurnby Lodge, was among the many people intrigued by the phenomenon, but said it made her feel slightly anxious.

She said: "To be honest, at first I thought it was another planet because of its circle shape, but also because I'd never seen anything like it before.

"I told my daughter to come and have a look at it, and she said it was similar to when petrol and water mix, but I told her that of course it wasn't that as there isn't any petrol in the sky.

"I then went to my mum and dad's, who live just down the road from me, and my dad said it was a rainbow, and my mum said that it was unlike anything she had seen in her life. She's 52 years old."

On Twitter, Leicester Schools Welcome Refugees said that a similar cloud formation appeared in Birstall at 4.30pm this afternoon.

Mercury photographer Chris Gordon captured the phenomenon, which was only briefly in the sky, on camera.

He said: "It's amazing. I've never seen anything like it. It's very reminiscent of a rainbow.

"I decided to take the picture as everyone in the office was so excited about it. Plus, I've always loved sunsets - they're my favourite spectacle."

Posts on Twitter suggested the spectacle was visible all around the UK.