Bessie Hawkes is used to dealing with the public. In her time she has run a fish-and-chip shop and a menswear store. Now she has wound her hair into a bun, wrapped a shawl around her rough dress and become the wife of a poor chainmaker. Her job is to stand all day in front of the iron range of her two-up, two-down cottage, chatting about her pots and pans and her privy ('only one hole, very posh'), her scrubbed kitchen table and treasured sewing machine ('see the mother-of-pearl on the drawer knobs').

For the visitors to the Black Country Museum in Dudley, Bessie is a vital link with the past, along with her neighbours Murphyn Beresford, a former bus conductor who plays Mr H Emile Doo the chemist; Fred Powell, who plays a foundryman, as he was in real life (his father made the brasses for the Coronation horses in 1953); and Jean, the shop assistant in Mrs Gregory's general store.

Bessie really does come from a long line of Black Country miners and asphalt workers. She dresses, she says, just as her grandmother did. 'I do play the part, but this house is so familiar to me. When I first stepped in here it felt like my place. Of course, you hear a lot of the same comments and questions every day, but I love it. There's never been a day in 13 years when I didn't want to come to work here.'

Ian Walden, the museum director, does blanch at the expense, but his group of 'live interpreters' has helped to hike up visitor numbers from 9,000 when the museum opened in 1978 to 265,000 last year.

Mr Walden's cast of Black Country folk are part of a growing army in the service of historical 'infotainment'. Our desire to day- trip into yesteryear at historical attractions has already mopped up hundreds of set designers, costumiers, musicians and odorologists (smell that fresh bread, that new- mown hay) and turned the faking of the past into a major industry. Now every museum marketing department and town tourism officer seems to want people in period outfits who can bridge the gap between the public and the artefacts or places they have come to see.

These costumed crusaders seem to be everywhere. They are playing Roman slaves in Colchester Castle Museum; medieval monks, Elizabethan wenches and Jacobean plotters in the Tetley's 'social history of the pub' attraction in Leeds. They're in the Tower of London and Hampton Court. Later this summer they'll be in the Bank of England.

They're making candles and pulling teeth in Ironbridge; turning schoolchildren into paupers at the Quarry Bank cotton mill in Cheshire; taking cover during air raids in Dover; and waiting for D-Day at the air force museum in Duxford, Cambridgeshire.

Live interpreters have their own recruitment agencies, seminars and consultants, and a brand new organisation called the European Theatre in Museum Association, which aims to 'attract new proponents and techniques and raise the profile of live interpretation for the exciting times ahead'.

Museum-goers don't necessarily want to return to the days when guides at historic sites were tweedies who could bore for Britain on plasterwork or the details of medieval fortification. We don't want to be greeted by people who see it as their job to guard history rather than explain it. At the other extreme, we tend to avoid the full metal jacket re-enactment groups such as Sealed Knot, fearing they might be driven more by a personality disorder than a love of history and could be a bit unpredictable in their pike action. But are costumed interpreters the answer?

At the Black Country Museum (as well as at Blists Hill 'Victorian village' at Ironbridge and at Wigan Pier museum) the chosen period is one which shades into living memory. As a result, Bessie Hawkes finds she spends less time explaining the life of a chainmaker's wife than acting as a conduit for the punters' own recollections - listening to stories from the half-remembered past of Belfast sinks and gas mantles, Dutch ovens and milk churns, of the neighbourliness and the hardworking respectability of those days when brass was brass and doors were solid wood. This is not history but reminiscence professionally indulged.

Among the interpreters, arguments rage about how the job of 'bringing history to life' should be done, and by whom. Should interpreters be local people, as at the Black Country Museum? Can amateurs be trusted in a situation where people are going to believe what they are told? Should costumed characters be flogging garden furniture and decorative ironwork, as at Ironbridge? Is the performance of a themed play by interpreters less intimidating for the visitor than being personally accosted by a friendly Viking in full fighting gear offering mead from his helmet?

Jane Malcolm-Davies runs Past Pleasures, the company that provides the team in the William III and Tudor apartments at Hampton Court, providing information on the 'soft' history of manners, costume, court life and royal entertainment. She is adamant that the interpreters should not be actors, real or manque. 'Our people are specialists,' she says, 'historians, linguists and musicians. Our latest recruit has a doctorate in 17th-century poetry. What they have in common is a passion for sharing their enthusiasm for the past.'

Past Pleasures is doing well: it has an annual turnover of more than pounds 300,000. Last weekend the company was in Tunbridge Wells, doing a dry run of the 'Georgian Festivity' that the town has booked for the first week in August. Eleven interpreters playing 18th-century characters mingle with the crowd, dropping curtsies and bows and bits of period chat, and taking the waters at Chalybeate Spring. There is period dancing and song, medical advice from Dr Theophilus Dobbs and a sermon from the Rev Elton at the local church. (Mr Elton is played by a civil servant who tells me he 'felt his calling' early in life.)

Past Pleasures compares its work with The Archers - 'an enjoyable soap opera that is also a public information service'. But what kind of information is the paying public interested in hearing? Only, it seems, reassuringly lightweight social history. Only the kind of history you find on tea towels. Anything more provocative and there's trouble.

Everyone in the business knows the story of what happened at the Louisbourg fortress in Canada when verisimilitude got out of hand. Interpreters dressed as 18th- century militiamen played their parts to the full. They were rumpled, rude, dirty and demoralised, because that's how they would have been. The tickets were collected from the visitors by 'syphilitic whores' of the type that hung around the fortress. Faced with this amount of reality, the history- loving public beat a hasty retreat and the project was closed down.

Black Country Museum, 021-557 9643

(Photograph omitted)