In October 1941, German soldiers dismantled the Amber Room at the Catherine Palace outside St Petersburg, Russia, for transport to Königsberg (now Kaliningrad) in the “Greater Reich”. There, the chamber - made in the 18th century from 30-foot panels of gold and Baltic amber, and gifted by Prussia to Tsar Peter the Great - was put on exhibition until the spring of 1945 when it vanished in the chaos of the war's end. Now a group of amateur treasure hunters claims to have located the loot in an underground cavern.

The team, fronted by a member of the German parliament, says that its electromagnetic tests have pinpointed two tonnes of precious metal in a disused mine at co-ordinates listed in the diaries of a Luftwaffe signaller. Diggers have yet to reach the “find”.

Whether or not the Amber Room has been, or ever will be, discovered - and sceptics believe that it was destroyed by fire before the surrender of Königsberg - the story shows that treasure hunting, the stuff of Indiana Jones films, remains a pastime in the 21st century. So what is left to find and how can you get involved?

The UK has few known “lost treasures”. Clive Sinclair, of the National Council for Metal Detecting (NCMD), says that the one big exception is King John's treasury, which was lost in 1216 when the royal baggage train took an ill-advised shortcut across the Wash, off East Anglia. This was much sought after by American amateurs in the 1930s, but Mr Sinclair knows of no dedicated searchers today. “The search area is wide and it would be well below detector range,” he says.

When treasure is found in this country, it is usually by chance. Metal detectorists unearth countless small, low-value items - copper coins and belt buckles, for instance - and sometimes stumble on something much more significant. A recent example is the Harrogate hoard of Viking gold and silver, found last year by Andrew Whelan and his son, David. The hoard included objects from as far afield as Afghanistan.

The Treasure Act requires finders to report all finds that could be “treasure” to the coroner. As a rough guide, this would be anything more than 300 years old containing gold or silver. The Whelans' haul was declared treasure trove and will be offered for sale to museums at market value of £750,000-plus. After a standard pre-agreement, the proceeds will be split between the finders and the landowner.

Despite the lucky nature of most important finds, Mr Sinclair says that detectorists can increase their chances by searching close to historical sites and lost villages, churches and manor houses - all traceable on maps and documents at county records offices. The £2.5 million Middleham jewel, for instance, was found close to Richard III's childhood home of Middleham Castle, Yorkshire.

Getting started costs from around £200. Local detecting clubs, listed at www.NCMD.co.uk, can help. Before setting out, visit www.finds.org.uk, the website of the British Museum Portable Antiquities Scheme, which maps and catalogues finds in England and Wales, allowing experts to interpret their distribution.

Would-be treasure hunters who want to search for something specific have better prospects away from British soil. Among potential targets are pirate treasures on Cocos Island, off Costa Rica, and the fortune said to have been buried with Attila the Hun somewhere in Eastern Europe. A more recent option is “Yamashita's Gold” - riches stolen by the Japanese in South-East Asia during the Second World War and, some say, secreted in a network of tunnels and caverns in the Philippines.

Starting a serious search for one of the big lost treasures takes huge commitment. The German group that has “found” the £260 million Amber Room spent 12 years and tens of thousands of pounds in the process. Under German law, if it does recover the room, or any other loot of the same era, all will go to the State and may be returned to Russia.

A more lucrative search can be for treasure at sea. Thousands of wrecks are well documented, most from the 16th to 18th centuries. These are targeted by well-resourced salvage companies, such as Odyssey Marine International, which has wrangled with the Spanish Government over ownership of half a million gold and silver coins from a galleon wreck it calls Black Swan. But amateur outfits - notably the South West Marine Archaeological Group (SWMAG) - have also had success.

In 1997 divers from this British organisation discovered the wreck of an unidentified 18th-century vessel, together with the largest cache of Moroccan bullion found in Europe, at the Salcombe cannon site off Devon. The hoard was recovered in close liaison with English Heritage and sold to the British Museum for £90,000. Mick Palmer, of SWMAG, says: “Unlike some groups, we do not make personal gain. The proceeds of the sale were all reinvested in new equipment, which was a big help.”

Mr Palmer, who works full-time as a director of a construction company and dives about once a month, says that those interested in taking up the hobby should contact the Nautical Archaeology Society (nasportsmouth.org.uk). “You need to have diving qualifications from the British Sub-Aqua Club,” he says. “Most SWMAG members spend about £3,000 a year on their hobby - for no cash return. We come from all kind of backgrounds: ex-navy, bank managers, solicitors, surveyors.”

Information on the legalities of diving wrecks is available from the Receiver of Wreck (MCGA.gov.uk/row). All wreck material found in UK waters must be reported here, though Mr Palmer, says that finders will be rewarded, with either the object itself or a salvage fee. He adds that there are plenty of opportunities for non-divers to get involved in marine archaeology on land, via archival research, for instance. Armchair treasure hunters with a passion for profit rather than history, meanwhile, can invest in a salvage business such as Odyssey, which is listed on Nasdaq, although this is high-risk.

Top three lost treasures

The San José was a Spanish galleon sunk by British ships off the coast of Colombia in 1708, with wealth worth an estimated £1 billion on board. American salvagers claim to have found the site, but a search of the supposed co-ordinates in 1994 turned up nothing.

Cocos Island, off Costa Rica, is thought to conceal two major treasures - one stashed by the pirate Benito Bonito, the second by the mutinous crew of the British ship charged to evacuate the wealth of Lima to Spain before Simón Bolívar's advance.

Yamashita's Gold takes its name from the Japanese general in charge of imperial forces in the Philippines, where it is said to be hidden, from 1944. It is alleged to be worth hundreds of billions of pounds. Sceptics doubt its existence and conspiracy theorists believe that it was recovered by the US and Ferdinand Marcos.