COLLECTABLES / On the roadshow to riches: Could granny's knick-knacks be valuable antiques? Madeleine Marsh goes behind the scenes of a TV show for the hopeful

LIKE MANY of its finds, the BBC's Antiques Roadshow has been in the family a long time. This month saw the launch of its 15th series, which will culminate in the 150th programme. Like the omnibus edition of The Archers, and newspapers by the kilo, it has become part of the Great British Sunday. It commands an audience of 13 - 14m (beaten only by the soaps in the BBC Top 10), and has caused a generation of viewers to root through its possessions looking for that little item inherited from granny, or bought from a jumble sale for 25p, which might be worth a fortune.

Britain is the perfect venue for the show. The British love queueing almost as much as they love television, and - as Roadshow expert David Batty has noted - 'there are more antiques per square mile in Britain than in any other country in the world'. Even after 15 years of trekking around the country, every roadshow is guaranteed to bring surprises.

Six weeks before each recording, advertisements are placed in local papers. People with small items for valuation bring them along on the day; anyone with larger objects is asked for photographs. If the piece turns out to be interesting, BBC staff will arrange transport. Other than that, there is no 'planting' of juicy discoveries. Each episode is recorded in a single day, and nobody knows what is going to come out of that piece of crumpled newspaper until after the doors have opened at 10 am.

When I arrived at Beaulieu Motor Museum at 9.30 on a cold and windy October morning, there was already a queue of 100 Roadshow hopefuls. Many looked at least as old as the objects they were bringing in. Seasoned day-trippers, they formed a cheerful and orderly line, swapping jokes and almond slices; they were laden with packed lunches, umbrellas, autograph books, the odd fold-up stool and innumerable family treasures. People don't just come to a Roadshow with one or two items, but with huge cardboard boxes packed to the brim with mystery objects wrapped in newspaper.

As the doors open, the crowds waddle through to the reception desk where they unwrap their treasures and are given tickets, directing them to the relevant expert's table - and often another long wait. An average Roadshow attracts 3,500 visitors (though numbers of 5,000-plus have been recorded), bringing with them up to 20,000 items; once inside you can easily queue for two hours for the more popular tables.

'A couple of years ago a woman fainted in the silver queue but refused to let the St John Ambulance Brigade take her away,' recalls ceramics specialist Paul Atterbury. She apparently cried 'I haven't seen the expert,' and they had to carry her over to him on a stretcher. 'Unfortunately, Madam,' he said, 'this isn't worth dying for. Get off to hospital.'

Some people come simply to see the experts. 'I'm not really bothered if my bits are worth anything,' one of a group of large and jolly ladies assured me. 'I've come because it's the BBC Antiques Roadshow - and I love it.' 'I wanted to see that John Bly,' confided her friend, blushing. 'I think he's lovely.'

At every Roadshow, there are 20 experts on hand, drawn from a stable of 60 dealers, auctioneers and academics. Some act as advisers to major museums and collectors. 'I like to think of it as the greatest travelling brain on its particular subject that has ever existed,' says John Bly.

You have to be good with people as well as objects to be a successful Roadshow expert, and tact is almost as important as expertise. Of the 20,000 objects they see, probably 95 per cent will be nondescript or rubbish, and fewer than 50 items will be filmed. 'The extraordinary finds are very rare,' says Paul Atterbury, 'but whether it is fearful tat or a pounds 20,000 piece, there is always something to say. And sometimes the worst things have the most wonderful stories or people attached to them.'

During my visit, four men arrived dragging an enormous piece of antiquated farm machinery across the floor. 'My goodness] What an absolutely superb object,' enthused Victoria Leatham, in what was clearly Roadshow-speak for 'What the hell is this?' A true professional nevertheless, she hitched up her skirt, sat down on the machine and eventually decided it was for carding wool. 'Very difficult to put a value on it,' she said. 'It should really be in an agricultural museum, but thank you so much for bringing it in. What tremendous fun.' The four men departed happily to put the instrument back in the barn where it had been for the past 50 years.

'No one is going to make you feel stupid for having brought something in that's only worth 50p,' claims the programme's executive producer, Christopher Lewis. On the ceramics table (always the busiest at any Roadshow) Lars Tharp, handling a pair of hideous green china boots the colour and texture of diseased liver - and about as valuable - was carefully explaining to their owner the difference between hand-painting and transfer-printing. Meanwhile, Henry Sandon was looking with apparent enthusiasm at what was probably his 50th Japanese porcelain eggshell tea service of the day.

'Without doubt they are the most common objects we see,' he confided to me later. 'Everyone in the world seems to have been given one as a wedding present in the 1920s. They look very fragile, and nobody ever used them, which is why they have all survived.'

Though every Roadshow has its rarities, each one also brings in innumerable identikit items which are not shown on TV. 'What do we get every time?' muses silver expert Brand Inglis. 'Britannia metal teapots, lots of them. Birmingham toilet boxes with winged cherubs, dating from 1900 - 1905. They just pour in.' Over the years, there have been some major discoveries. 'I found the most newsworthy thing on the show,' says picture dealer Peter Nahum, his eyes shining with triumph. 'The lost Richard Dadd. I opened a cardboard sandwich and inside was this dark blue landscape, top quality in execution of paint and visionary feeling. I thought: 'It can't be] I've never seen anything like it in this condition, it's too good.' My brain was working at a million miles an hour. By almost psychic coincidence, I had actually handled every great Dadd that had ever come on the market. There are only 250 known examples of his work, and I realised I had hit the jackpot.'

Its owner, who was redecorating, had been about to throw the painting away. It was sold to the British Museum for pounds 100,000.

When an expert finds something good, the owner is asked to wait for it to be identified before it can be filmed. They are taken to the hospitality tent for tea and make-up (causing much embarrassed giggling as men have their noses powdered), while the expert checks the facts - if necessary - with reference books and colleagues. Expert, owner and object are all reunited on camera.

But a wait in the hospitality tent doesn't necessarily mean you have hit the jackpot. 'Well,' said one expert cheerfully to a couple bearing an Art Deco statuette. 'Last year your figure would

have been valued at pounds 400 to pounds 600, but with today's prices it is only worth pounds 150.' The camera moved in to catch the spontaneous response, which was distinctly glum.

Far happier was the young man who had found a box of 'funny sort of marble things' in the loft, which Victoria Leatham identified as a set of early 19th-century intaglios, or relief carvings - 'one of the most exciting things I have ever seen on the Roadshow' - worth pounds 1,400 to pounds 1,800. Convention dictates that, on camera, most people swear never to part with their treasured family heirloom. But likely as not, the item - if it is valuable - will be in London for the next season's auctions.

As the day draws to a close at 5pm, the exhausted experts make tracks for home, the crew take their final shots, and the visitors depart with their newly identified family treasures. 'I've had such a lovely day,' concluded one woman, deliberating over a last-minute purchase from the Antiques Roadshow shop. 'My teapot was worth pounds 90, my postcards 50p each and there are ever such a lot of them - and I got to shake hands with Hugh Scully.'

She finally decided to buy a mug bearing the logo 'I've been valued at the Antiques Roadshow'. 'You never know,' she quipped to the assistant, 'it might be worth something one day.'-

(Photographs omitted)