The centenary of the First World War is set to trigger a boom in the underworld memorabilia market with thieves targeting museums during four years of high-profile commemorations.

Security experts warned that increasing interest has driven up the price of medals on online auction sites and experts fear that poorly-protected exhibitions, battlefield sites and wrecks are all at risk of plundering for profit.

Many medals from the era are made from silver and the high price of the precious metal – which topped £2,000 an ounce on exchanges earlier this year – is likely to make them targets for criminal gangs.

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Museums are likely to put on display artefacts from the Great War in the coming years previously held in storage or archived. Many museums have plans for a rolling series of exhibitions to mark 100 years since the start of the war, major events like the battle of the Somme, and the end of the war.

“The price of first world war medals is going up and criminals are incredibly good at latching on to price increases,” said Vernon Rapley, the head of security at the Victoria and Albert Museum. “Quite a few medals of the time are silver and there are likely to be an increased number of forgeries to do with the First World War.”

Senior police said that top-level organised criminal gangs with contacts across the globe have increasingly moved into the heritage market attracted by the high sums and easy portability of some takings.

The industry warned that television programmes such as the Antiques Roadshow and Cash in the Attic – with its focus on the estimated value of antiques – have attracted the interest of criminals. The industry has estimated that the theft of art and antiques in Britain every year exceeds £300 million with 200 crimes committed against listed buildings across England every day.

“There is an increasing threat that less organised criminals will use more extreme levels of violence to achieve their aims,” according to a threat assessment published yesterday by the Association of Chief Police Officers (ACPO).

The campaign against the illegal trade – which is second only to the drug trade in terms of proceeds – is hampered by a fragmented system of tracing stolen items. ACPO yesterday (Mon) launched a new strategy in concert with groups like English Heritage with plans for a new national intelligence database.

Det Supt Adrian Green, who is heading a major inquiry into stolen Chinese antiquities, said: “This is top level international organised crime. Once you have logistics and the financial capability, criminals can swap between antiques, firearms trafficking or humans.”