It descended yesterday; a thin cloud lingering on the pitch like dry ice left on stage after the finale of a magician's act.

As all these clouds drifted lazily past the setting sun, a large smudge of multicoloured light emerged through the shroud of thin cloud.

Scientists have speculated that global warming could cause high thin cloud cover to increase, thereby increasing temperatures and humidity.

The clouds did clear but during their most important observations the sun was covered by a thin cloud.

Iridescent clouds are created by minute water droplets - as small as 0.001mm - of roughly similar size in very thin clouds.