Britain's most spectacular commemoratives, No65: 2001 Weather 27p

The four values in the Weather set are designed to be viewed as a group, completing the circular face of a barometer, and this is best seen in the format of the miniature sheet, which is itself circular.

The set is a veritable riot of colour and amusement, with many intriguing design elements which repay closer study, such as cats and dogs falling from the sky in the 19p.

But most striking of all is the 27p value, hinting at fair weather by way of a smiley-faced sun, with the value denominator doubling as a pressure gauge.

Thanks to the use of thermochromic ink, its reddish violet colours should change to light blue when subjected to a heat source.

Design: Howard Brown.
Printing: gravure by De La Rue.