LONDON - WITH thousands of bags lost at Heathrow's Terminal 5, some people will never see their luggage again.

So what happens to bags when the hunt for their owner ends?

They end up in an auction at a small warehouse in South London called Greasbys, BBC News reported.

Greasbys, along with a number of other auction houses in Britain, sells luggage once airlines have given up attempts to return bags to their owners.

The BBC caught up with Mr Gary Marshall, from Enfield, north London, a regular at the auctions which he has attended weekly for more than a decade.

Last week, he bought four cases - a modest haul compared with his average of between 15 and 20 each week.

The 46-year-old former engineer told the BBC that buying at these auctions, which started out as a source of extra money, has become his "livelihood" as he sells the cases and their contents online and at a market stall he runs.

"It isn't easy to make money out of this," he warns, after explaining that he can sell the goods for up to six times the amount he paid.

"The more I buy, the better my chance of something decent. It's a gamble. You could get a bag of crap or open it to find designer goods, which you can then sell on eBay."

Suitcases purchased by BBC News for an average of ?20 (S$53) appear to support Mr Marshall?s theory.

Their contents provide snapshots of holiday hopes: Short-sleeved shirts and T-shirts are mixed in with denim miniskirts, bright beach towels, swimming trunks and several photographs of a young man in Hastings.

No toiletries, books, shoes or electrical goods suggests many items had disappeared, said the BBC.

Recent problems with the baggage system at Heathrow's Terminal 5, which has caused a backlog of up to 28,000 items, have thrown the issue under the spotlight.

The airline said about three months are spent using a "manual tracing process" to identify owners, which means none of the bags currently being sold at auction would be from T5.

A BA spokesman told the BBC that all proceeds from auctioned luggage goes to charity.

"The vast majority of bags are reunited with their owners. Every effort is made to trace them," he said. "But, unfortunately, there are a few occasions when this is not possible."

All major airlines use the World Tracer system to assist in the recovery of lost baggage.

The system offers up to 100 days of continuous tracing from when the passenger reports their baggage as missing.

It looks to match tag numbers, baggage type, colour and brand of mishandled bags to those held on its database.

When a match is achieved the item is forwarded on with a "Rush Tag" to the airport nearest the owner and the baggage is delivered to the customer's door.

After a three-month period of trying to reunite a lost item with its owner, the item may be auctioned with proceeds going to charity, but the majority of lost bags are returned to their owner within 24 hours.