THIS is a story of greed and sacrifice, globalisation, the desperate scramble for dwindling natural resources, and the rearguard fight to save the planet from pollution.

It starts in Plymouth with one of the most shocking crimes the city has witnessed for years – and yet nobody was hurt and nothing of great monetary worth was stolen.

When thieves prised four bronze plaques off the Naval Memorial on the Hoe this week they hoped to make a few hundred quid selling them for scrap. Instead they hit a raw nerve which led to a storm of outrage that made the haul impossible to sell.

Scrap metal merchants in Plymouth and around the country were on the alert for the plaques after a wave of publicity locally and nationally. One was recovered in the city centre after a dealer reported it being handed to him. Three others were retrieved by police on Thursday.

Angry war veterans questioned how thieves could even think of desecrating the memorial to those who gave their lives for our freedom.

The answer is money. Prices of most metals have soared in the last few years because of hugely increased demand from the fast-growing economies of China and India.

Take just one as an example; copper reached £4,363 a tonne this week on the London Metals Exchange, roughly 55 per cent higher than the start of 2007 and four times the 2003 figure.

Prices of scrap metal have increased dramatically too – and bronze is 90 per cent copper.

As prices rise, so do the incentives to reduce waste and recycle more – and so does the temptation for thieves.

Copper has shown one of the biggest increases because of its versatility, from electrical wiring to domestic plumbing. But prices of other scrap metals such steel and aluminium have risen sharply, too.

Criminals have been quick to spot these developments. They have stopped commuters in their tracks in Wales by stripping copper electrical circuits from railway lines, stunned art-lovers by stealing bronze sculptures by Henry Moore in Hertfordshire, and left managers at a Devon factory bemused by making off with a three- and-a-half-tonne propeller made of bronze and aluminium outside their Newton Abbot plant.

“Vicars can relax because the price of lead has gone down,” says Plymouth scrap metal dealer Joe Kitt, injecting a note of grim humour and referring to thieves' more traditional targets: church roofs.

You can forget, though, the TV crime drama image of scrap as a dodgy business and a favourite outlet for criminals wanting to launder money or sell on anything metallic and valuable. By law, all dealers have to be registered by their local authority – in Plymouth's case, the city council. Depending on what they handle they may also need an Environment Agency waste management licence.

Mr Kitt shows me the records he must keep for his North Corner Metals business to stay within the law: the date, time, weight, description and value of every amount of metal he receives and the details of any vehicle it arrived in. Similar details must be kept for the metal he sells on.

A sign outside the yard in Rendle Street, Stonehouse, warns that nothing known to be stolen will be accepted and CCTV is in operation.

“If they can't show me ID and the vehicle details and it doesn't feel right, I won't take it,” says Mr Kitt.

“Even if I take something in good faith I can lose out. I bought some lead at 8.10am one day – everything seemed right – and at 4pm the police came in, said it was stolen and seized it – cost me £300. I got none of that money back because the court didn't issue a compensation order when the man was convicted.”

As for theft of the war memorial plaques, “Any scrap metal dealers would be savage about that,” says Mr Kitt. “It's unreal, isn't it? I can't believe anybody could steal something like that.

“The police and an army man – a captain – came round to ask if I'd heard anything. The captain said if he caught them their name would be added to the list of the dead.”

Mr Kitt is one of the few owners of small companies who doesn't bemoan the condition of the economy. “Business? It's fine,” he says with a smile. “I'm selling copper at £4,000 a tonne. That's a lot higher than it was: but that's not just any copper. that's the top grade.” Or, in scrap parlance, 'bright wire' – pure copper found in electrical wiring.

Even that has to be processed – the insulation cable stripped off – and most of the copper that comes in isn't pure. Tubing is mixed with other, cheaper, metals for strength and often encased in non-copper joints, which must be removed.

Out in the yard, next to the machines to cut, trim, squash and bale, are piles of copper, brass, lead and stainless steel. North Corner takes mostly 'non-ferrous' – non-iron-based metals – and sells the material on to larger dealers.

Higher prices are encouraging builders to recycle instead of bulldozing scrap into the ground on sites, and the building boom in a regenerating Plymouth means a steady supply of old interior fittings to be disposed of by scrap dealers.

Mr Kitts provides a natural history element to the story; he is an endangered species.

“There aren't many of the old rags (rag-and-bone men) now. I'm the original Steptoe,” he adds with another laugh, proud to be associated with that icon of TV comedy.

He counts off four smaller dealers who used to operate in the city centre. Now scrap's generally a big-money operation and many smaller dealers have been bought out.

Their adverts in the phone book might be no more impressive than Mr Kitts', but European Metal Recycling, which has two sites in the city, is a UK wide business worth £1.1billion and Sims Metal Management, which has one, a £3.8billion Australian international giant.

Has Mr Kitts had any buy-out offers? “No. I'm too small. I don't rock the boat. We process the smaller quantities and sell on to them.”

I doubt if he'd even want to sell the business if approached. It's been a family affair for 30 years. Son Danny and daughter Joanne work there and Joe's the sentimental type.

He shows me boxes and boxes of brass ornaments, such as small Native American busts and dogs and decorative taps in the shape of fish, dolphins and other animals.

“I couldn't have them melted. Couldn't bear the thought. I love animals too much!” He has a smallholding with livestock and pets.

“Sad, isn't it? People get fed-up with polishing stuff and it gets chucked out”, he says. “Look at the work that's gone into this stuff. Nobody appreciates it any more.

“I can't stand the thought of something beautiful being melted down.”

Criminals, though, are less sentimental. As the price of metal continues to soar, they've even taken to cleaning up after other illegal activity to make a few quid.

Five years ago there were worries that new European regulations concerning the scrapping of unwanted vehicles would lead to abandoned cars clogging our streets, but with scrap steel at £200 a tonne – roughly the weight of a family car – vehicles served with removal notices in Plymouth are being taken by thieves before the authorities can legally remove them.

As prices of commodities such as metals and fuel continue to rise around the world, so do the chances of thieves changing their habits and striking closer to home.

Crimestoppers South West regional chairman Bob Widdecombe says domestic heating oil tanks are now being targeted by Plymouth thieves.

“You'd never have thought of crimes like that happening a few years ago,” he says.

Crimestoppers offered a substantial reward to help recover the plaques. Anyone with information about this or other incidents should contact Devon and Cornwall police on 08452 777 444 or Crimestoppers on 0800 555 111 quoting police reference EC/08/7109.