Answer crystallises after 23 years

A professor yesterday told how it took him 23 years to do a numerical calculation that "is of no use whatsoever".

Les Woodcock, physical chemistry professor at the University of Bradford recently completed the mammoth sum to find out whether one form of crystal was more stable than another but said that it was "a long and tedious calculation".

He cheerfully admitted the discovery, which shows the crystal structure of a hexagonal close packed lattice is less stable than a crystal face centred cubic lattice, came about because he had been thinking about it for rather a long time. And he added: "It is not fashionable in UK universities to want to do something for purely academic reasons, for curiosity. It was my personal hobby horse."