Police have launched a nationwide blitz on the theft of metal, a fast-growing crime fuelled by rising prices on world markets and insatiable demand from booming Asian economies.

Favourite targets for thieves have been church roofs for lead, railway signalling for copper and road signs for aluminium.

Manhole covers, drain grilles and even commemorative brass plaques have also been disappearing in a crime wave estimated to be costing the country over 300 million pounds a year.

Works of art have been favourite targets in recent years, particularly those cast in bronze.

In 2005, a 3 million-pound sculpture by Henry Moore was stolen in Hertfordshire and a few weeks later a 600,000-pound work was taken from the grounds of Roehampton University in southwest London.

The Association of Chief Police Officers (ACPO) said on Tuesday that 38 forces were visiting scrapyards and stopping suspect vehicles in the two-day blitz, which began on Monday.

ACPO's lead on metal theft, British Transport Police (BTP) Assistant Chief Constable Paul Crowther, stressed that metal theft was not a victimless crime.

"Thousands of people have seen their community facilities stolen or damaged by thieves looking for a quick gain, or have suffered service disruption to railways and telecoms," he added in a statement.

"The problem ranges from opportunistic to large-scale organised theft.

"This has a huge impact across the country - not just financially, but in people's everyday lives."

The BTP says the theft of metal from the railways increased nearly 70 percent last year and caused 2,500 hours of delays.

BTP Chief Constable Ian Johnston has declared the issue their second-biggest challenge after terrorism.

ACPO said the police blitz was being supported by the brewing industry, which loses a lot of aluminium beer kegs, and the rail, telecoms and power industries.

The British Metals Recycling Association, whose 300 members represent the 5 billion-pound UK industry, launched a joint effort with ACPO last September to help stem the problem.