As rainbow stretches over Sheffield skies, did you know city holds world record for the longest lasting bow?

This impressive colourful arch was spotted stretching over the city centre this morning - but it will have to go some way to beat an incredible record set in 1994.

For on March 14 in that year, a rainbow was apparently observed continuously over the city for an incredible six hours - the colourful weather spectacle lasting from 9am to 3pm.

There's little documentation out there, but the rainbow was apparently observed from the University of Sheffield for most of the day.

Rainbows are formed through reflection, refraction and dispersion of light in water droplets resulting in a spectrum of light appearing in the sky. It takes the form of a multicoloured arc.

Rainbows can be full circles; however, the average observer sees only an arc formed by illuminated droplets above the ground.

In a double rainbow, a second arc is seen outside the primary arc, and has the order of its colours reversed, with red on the inner side of the arc.