No jackets required: Many Irish emigrants would kill for a packet of Tayto's cheese & onion crisps. Roberta Mock searched in vain for a potato in a suit

It's difficult to get excited about crisps. Golden Wonder and Walkers do their best, secreting little blue bags of Monopoly money in their packets and introducing implausible new flavours, like lamb and mint. But snack food is not a glamour industry.

With a bit of promotion though, it could become part of our heritage industry. Tandragee in County Armagh is dominated by its 17th-century castle, a mossy, imposing building at the top of the main street. Elsewhere one would expect to see the flag of the National Trust hoisted from its battlements. In Tandragee, the castle is a crisp factory.

Not just any crisp factory, though: it's the home of Tayto Crisps. Many a sentimental tale is told about potato bread, fried breakfasts and soda farls, but it is a lesser-known fact that what every exiled Irish person really misses is his bag of Tayto cheese & onion. The lurid yellow bags feature a cartoon strip on the back which depicts Tayto Castle 'set in the heart of Ulster countryside'. There is a secret room where special ingredients are added while Mr Tayto, basically a potato in a suit, runs around with a peculiar frying pan. It's as if the company had employed Roald Dahl as a promotions consultant.

The PR is obviously successful as there is currently a two- month waiting-list for group tours of the Castle. Some prospective visitors are students eager to discover the secret behind one of the most modern crisp factories in western Europe. Others, like myself, are simply seduced by romantic images of fairytale castles and the possibility of glimpsing a six- foot tall Mr Potatohead.

I was disappointed. None of the factory is actually housed in the castle itself. Tandragee Castle was bombed during W W II and prohibitive renovation costs prevent its use. Tayto has added its massive sheds round the back of the castle's formidable shell.

At no point during the 40- minute tour was Mr Tayto spotted. Apparently the costume is thrust upon some hapless Tayto employee only when primary school groups are visiting the factory. There was, however, a genuine 'Secret Flavouring Room' where the Cheese & Onion mixture is supposedly added. I also learned an awful lot about the production stages which transform a humble potato into a crisp.

For instance, it takes 40 seconds to peel a potato. These potatoes are sliced by blades that are changed every two hours. The slices are blanched to give a more even colour and are fried at approximately 180 C.

The tour takes in the large air-ventilated bays which store a capacity of 5,000 lbs of potatoes and miles of conveyor-belts leading to mud-washing machines, dump boxes, rotating drums and enormous fans. The noisy, steel production line looks like it has been hammered together by some mad inventor but is apparently state-of-the-art crisp machinery called Ishida.

It is perhaps churlish of me to complain at the lack of access to a hazardous ruin and the non-appearance of a cartoon character. Tayto runs its tours as an educational exercise and charges no admission fee. I should be proud to witness an expanding British industry which employs nearly 60 per cent of the local population. But mainly I am pleased to have received two Tayto mugs and a 'Tayto Tingle' T-shirt so that I can say I've been there.

Tours arranged through Tayto (Northern Ireland) Ltd, Tandragee, Co Armagh, N Ireland (0762 840249)

(Photograph omitted)