Oh for a troll or two . . . or twelve: First a cult in the 60s, they're back with a vengeance. Who's responsible?

FIVE years ago, a freelance toy researcher called Mike Mandolay saw a children's show in a small theatre during a weekend trip to Copenhagen. 'The company employed four dwarfs; I thought they were really unappealing, but the kids there absolutely loved them.' he says.

'One of these dwarfs wore a breastplate, and could make wishes by rubbing it. After the show, the kids were invited up to rub this dwarf's chest; they adored that.'

At 44, Mr Mandolay is old enough to remember trolls from the last time around, in the Sixties. He thought about developing an updated troll based on the dwarfs and decided to replace the breastplate with a wishing stone in the bellybutton - if you rub the shiny stone, your wishes come true.

'I went back to Britain with the idea,' says Mr Mandolay. 'The companies were pretty dismissive - not keen on bringing trolls back in.' Last year, though, they finally returned his calls. 'You have to be patient,' says Mr Mandolay.

According to Sara Stewart of Hasbro, the largest American toy manufacturer, two summers ago teenagers started wearing trolls on strings round their necks, as mascots in night-clubs. The manufacturers assumed that younger sisters and brothers would copy the older kids (unlike many of the 'nostalgia' toys around this Christmas, such as the hugely successful Thunderbirds figures, the trolls are not related to re-released television programmes). The hunch was right and the trolls, which cost from 99p to pounds 49.99, mopped up 43 per cent of the girls' collectables market this year, leaving rivals such as My Little Pony standing in the stalls. The wishing-stone version is the most popular of all.

Companies like Hasbro create most of their toys in-house, so a freelance has to be very good to compete. 'Outsiders have to be quite batty really,' says Ms Stewart. 'Someone who can see things through a child's eyes, and find something attractive which most adults would consider mad.'

Mr Mandolay has a good record for discovering cult hits - his was the mind behind the 'Drink and Wet' My Little Pony - when it wets itself, little hearts appear on the nappy. He also came up with the 'Drink and Burp' Cabbage Patch doll.

This Christmas Mr Mandolay is scouting round the Caribbean looking for a vegetable dye that can be used to produce brighter- coloured Playdoh, the modelling material that it is safe to eat.

(Photograph omitted)