Sheffield without Henderson's is like Scotland without haggis. But did you know that the cult relish is made by a staff of just three? Bill Knott meets the sauce-maker-in-chief - and some adoring fans

It is lunchtime at the Two Steps chippie in Sharrowvale Road, Sheffield, and business is brisk. The Pensioners' Special - a small fillet of cod in batter, with mushy peas and chips - is, at £1.50, deservedly popular. The home-made pies are also selling well, and Lucy, behind the counter, is definitely earning her crust.

It is lunchtime at the Two Steps chippie in Sharrowvale Road, Sheffield, and business is brisk. The Pensioners' Special - a small fillet of cod in batter, with mushy peas and chips - is, at £1.50, deservedly popular. The home-made pies are also selling well, and Lucy, behind the counter, is definitely earning her crust.

Nobody leaves the shop without anointing their lunch with a squirt from an old-fashioned, orange-labelled bottle. Henderson's Relish is practically mother's milk in Sheffield, a sauce so ubiquitous that even some hairdressers sell it, while occasional - but misplaced - rumours of its imminent demise cause a rush of panic buying throughout the city.

Henderson's is the consistency of Lea and Perrins, but with the flavour of a sharp, sweet brown sauce. Sold almost exclusively in Sheffield and the surrounding area, it has been made in the city since 1889. It is used as a relish on almost everything, and is indispensable both on local pies and on "'ash", Sheffield's native variety of meat stew.

Nor do you have to be a born Sheffielder to appreciate it. Lucy (from the chip shop) is from Kent, but now understands the virtues of Henderson's. "I'd never heard of it before I came here, but I'm definitely a convert: chips aren't the same without it. And if we ever run out of it, people complain."

Not far away, at the Taste café (and "Friday night bistro"), chef Jamie Bosworth is putting the finishing touches to his lunchtime special of seared scallops with a purée of mushy peas, rocket salad, Parmesan... and a reduction of Henderson's.

"I just treat it like balsamic vinegar: reduce it by half with a dash of sugar." It actually works rather well, drizzled over the scallops as a piquant syrup.

"You find it everywhere in Sheffield," explains Jamie, "and it's always at Bramall Lane [Sheffield United's football ground] next to the pies." However, its appeal is not restricted to the city boundaries.

"I've got family and friends in Sydney," he adds, "and they always order a case or two if they know I'm coming. God knows what they eat it with: Moreton Bay bugs, probably."

The hub of the Henderson's empire is a detached house on Leavygreave Road, opposite Sheffield University; in fact, about to be engulfed by the university. All the surrounding buildings have been demolished, leaving the factory as a Victorian outpost in a brave new science park, the giant earthmovers and cranes dwarfing the old red-brick house.

The office is equally anachronistic, dominated by an old relief map of northern England with an impressively rugged model of the Pennines as its spine. Henderson's T-shirts - popular with students, apparently - and the Henderson's cookery book are both on display. Managing director Kenneth Freeman and wife Pamela preside over a staff of three: Kate Boulton, who looks after the website and is bravely attempting to drag Henderson's from the 19th to the 21st century, and the two Sheffielders in the factory, Chris Kenny and Dougie Dyson ("as in 'oover").

The Freeman family have been in control of Henderson's for over 50 years: Ken became a director in 1986 and MD when he retired from his Liverpool medical practice in 1991.

The secrets of the blending room are preserved by polythene sheets and a "no unauthorised access" notice: not, one suspects, that the sheets are hiding a roomful of hi-tech gizmos. A large tin bath and a long wooden spoon are more likely.

Henderson's Relish looks like Worcestershire sauce, but it is a relish, not a condiment. Also unlike Worcestershire sauce, it does not contain anchovies (so is approved by the Vegetarian Society) and it is not fermented: the dominant flavours are vinegar, sugar, tamarind and warm spices. Oddly, the list of otherwise wholesome ingredients also includes saccharin; according to Ken, this is because the recipe hasn't changed since post-war years when sugar was scarce. The sauce does not, he stresses, contain Sudan 1: the only colouring is caramel.

Somehow, the company manages to produce 500,000 bottles a year from its tiny premises, supplying every major supermarket in the area, as well butchers and many small shops. The factory lease ran out in 1999, however, and the site is living on borrowed time. Ken is clearly reluctant to relocate, and would never countenance leaving Sheffield. Plans for expansion are vague: aggressive marketing and advertising campaigns are not part of the company ethos.

Besides, global distribution would rob Henderson's of its cult status. Many addicts will go to almost any lengths to assure a constant supply: Sheffield-born actor Sean Bean, for example, once bought two gallons of the stuff because he'd heard a rumour that Henderson's was going out of business, and nightclub owner Peter Stringfellow cannot eat a cooked breakfast without it; rumours, by the way, that Henderson's is responsible for his permanently tanned appearance are completely unfounded. Expats suffering withdrawal symptoms are responsible for the thriving website mail-order business, but, Ken notes approvingly, "we still get many handwritten letters". Troops stationed abroad are particularly avid consumers, and Iraq is awash with the stuff.

Production is year-round, although consumption is seasonal. According to Ken, "demand drops off in summer, then we have a great spurt just before Christmas." However, seasonal variations are not as great as they once were, perhaps because Sheffielders have started to embrace alfresco cooking: Henderson's makes an excellent marinade for barbecues.

Henderson's is also known for its special bottlings: occasionally the old-fashioned orange and black label is also decorated with the British flag - during the World Cup, for instance - or with more local colours. Both of Sheffield's football sides, United and Wednesday, once had their colours on bottles at the same time, giving fans a choice of which to buy. Shortages of the favoured bottle in particularly partisan areas were common.

Henderson's also does an original line in wedding invitations: a bottle of sauce may not seem like the most obvious or, indeed, romantic medium by which to announce impending nuptials to one's friends, but it is very "Sheffield" and, as Pamela Freeman says, "it's a good deal cheaper than sending out hand-printed cards."

The recipe, naturally, is a secret, although perhaps not as closely guarded as such an important treasure should be. Pamela admits, "I didn't even know the recipe until Ken broke his ribs last year and I had to take over. I forget where it is now: I think it might be in my purse."

As the staff assemble on the pavement outside the factory to have their picture taken, the passenger in a passing car winds down his window and starts applauding. Beaming broadly, he shouts: "Beautiful, that is, on 'ash, and on meat and tater pie!" One gets the feeling that a future without Henderson's is not something Sheffield would relish.

Henderson's Relish costs about 90p a bottle. For more information, see