The relative smallness of the world in the 21st century is well illustrated by the way that soaring demand for metals such as copper and lead in India and China, where the economies are booming, is resulting in a growing number of thefts from roofs in and around Bradford.

The rising global price of commodities which are increasingly in demand has made them attractive targets for thieves, who are stripping lead from churches and community centres and stealing the wire from railway signals.

The loss of the lead is proving to be an expensive nuisance. Not only is there the cost of having it replaced and of repairing other damage which might have been caused by water coming in through the roof, but there is usually a subsequent increase in the insurance premium. In the case of the youngsters of Wycliffe CE Primary School, Shipley, precious classroom time was lost when the start of term had to be delayed.

The theft of railway-signal cable can cause major disruption to passengers and is potentially dangerous to rail travellers and thieves alike - although if one of the latter was killed or seriously injured by a high-voltage shock while stealing the cable, it might deter others from embarking on similar crimes.

As it seems virtually impossible to catch the thieves in the act of stealing the metal, the clampdown by police and environment officers on Bradford dealers and their suppliers is a sensible way of tackling the problem.

If people find it increasingly difficult to make money out of the metal they acquire through crime, there surely will be less incentive for it to be stolen.