Treasurer's House has no deer park to walk around. Instead, as its contribution to this year's National Trust 'Great British Walk' season, it is offering ghoulish guided tours of York's sickelways in the company of Mad Alice. STEPHEN LEWIS reports

IF ever you see a Viking in a dark alley, says Mad Alice, there's only one thing to do. "Run for it! Vikings aren't very nice people."

She then proceeds to demonstrate why. She's led her unsuspecting group of sightseers and thrill-seekers round the side of Jorvik. Suddenly she turns on one of us - a perfectly pleasant woman by the name of Sally - and proceeds to demonstrate a gruesome form of Viking torture.

She presses Sally - surprisingly gently, it must be said - face-first up against the brick wall. Then she turns to the rest of us with a lascivious smile, and flourishes an imaginary knife.

"Taking the knife, you cut along the top of the shoulder blade," she says, demonstrating. "Not too deep. You go along to the spine, then down alongside the spine, creating a flap of skin." She mimes doing so, then puts down her imaginary knife.

"Now, you peel back that flesh to expose the bone. By this time, Sally should be making a lot more noise!" She glances pointedly at Sally. Sally obliges.

"What we're doing is exposing the shoulder blade," Alice continues. "Now, you get your fingers underneath the big shoulder blade, and pu-u-ull it up so that it stands on top of the shoulder."

Do that twice, once on each side, she says, and you have a poor victim with two flaps of bone standing up above the shoulders that look like eagle's wings. "That's why it was called the Blood Eagle," she explains brightly. "Round of applause for Sally."

You can say one thing for Mad Alice: she's got a ghoulish sense of the melodramatic.

Her name's not really Alice, of course. In real life, she's Alicia Stabler, a "slight actress" (her own words) who is a tour guide at Treasurer's House and, for the last 18 months, in the guise of Mad Alice, has been leading the aptly-named Bloody Tour of York.

Mad Alice may or may not be a real figure from York's past, admits Alicia. She may have been a woman called Alice Smith who was hanged at York Castle in 1823 for being insane - or, according to another version of the story, hanged in 1825 for poisoning her husband. There's no evidence in the records of anyone named Alice Smith having been hanged in York, however. Yet the myth persists - and whatever the truth of the legend, Alicia's Mad Alice makes a great, and suitably bonkers, companion for an evening walk around York's streets.

Her 'Bloody Tour of York' is effectively a guide to York's 'horrible history' - of which there is plenty. She doesn't touch upon ghosts - there are plenty of ghost tours that do that. Instead, she leads you through the snickelways and byways of York, regaling you with gruesome tales along the way.

For the next three weeks, she has adapted her tour so that it starts, every Wednesday evening, from the gardens of Treasurer's House. It's the historic building's contribution to the National Trust's Great British Walk season.

"We don't have a deer-filled estate to walk around," says Lisa Holden, the Treasurer's House visitor services manager. "So we thought 'what can we do that's a bit different?'"

The answer was, asking 'Mad Alice' to adapt her walk.

And great fun it is too - provided you're not too squeamish.

We meet in the garden of Treasurer's House at 6.30pm. There's a chill in the air, but a shaft of late evening sunlight is gilding the stone of York Minster into a burnished gold.

Lisa hands round glasses of warm, spiced mulled wine to keep the chill out, then Alice begins her tour.

First, with quite unseemly relish, she relates the tale of two murders that took place here right at the house itself. One, which happened in the 18th century when the house was divided into apartments, involved a husband and wife. Like most couples, they had their good days and bad days, Alice says. "And then, one day, they had a really bad day." The husband told his wife he wanted her to move out, so he could move his mistress in.

"That night, she crept out of bed in the middle of the night, went to the fire, picked up a poker - and beat her husband to death."

Then there was poor George Aislabie, who owned the house in the mid 1600s. In January 1674 he got involved in a duel at Grays Court over the 'honour of a lady' - one Miss Mallorie, daughter of Sir John Mallorie of Studley Royal.

Unfortunately, George was in his 50s, and his opponent much younger. "He was a sprightly young man in his 20s," Alice says. "You can imagine what happened..."

George was pierced in the arm, probably severing an artery, and carried back to Treasurer's House, where he died in the Long Gallery.

It's a suitably grisly beginning, but Alice is just getting started.

"How do you feel about walking around York with me?" she says, rubbing her hands. "The stories get worse!"

She leads us around the Minster's east front to the statue of Constantine, where she regales us with a story of the lost Roman legion - the ninth - which marched north from York to subdue the marauding Brigantes and was never heard from again.

Then she indicates St Michael le-Belfry church where, on April 16, 1570, one Guy Fawkes was christened. It gives her a chance to describe, with a little too much relish, poor Fawkes' fate. Discovered beneath the Houses of Parliament on November 4, 1605, with 36 barrels of gunpowder, he was stretched on the rack until he gave up the names of his co-conspirators. "His arms were stretched and stretched until his shoulders popped out of their sockets, and his arms were useless for the rest of his days," Alice says.

There weren't many days left. Guy and his co-conspirators were convicted of high treason. The punishment for that was to be hanged by the neck and cut down while still alive. "Then the privy parts were cut off and burned before the face, the intestines were taken out, and finally the victim was quartered and beheaded," Alice says. Not surprisingly, Fawkes didn't much like the prospect. On the day of his execution, in 1606, he foiled his executioners by leaping from the gallows and breaking his neck.

His tale proves one thing, however, Alice says. "Here in York we don't have very good terrorists."

Our tour takes us down Mad Alice Lane ("This is where I used to live!"), along Shambles - where Alice pauses for a gruesome telling of the story of St Margaret Clitherow, who lived at No 10 Shambles, and was crushed to death on Lendal Bridge for the crime of harbouring a Catholic priest - and on to Pavement. Here, in front of All Saints Church, she tells us how, in August 1572, Thomas Percy the Earl of Northumberland was beheaded on this very spot for leading a failed uprising against Queen Elizabeth 1. His head was put on a spike at Micklegate Bar, and his headless body was buried in an unmarked grave at St Crux' church, Alice says.

From there, it is on to Coppergate, and that demonstration of how to perform the Blood Eagle. There's a stop at Clifford's Tower to learn about the massacre, in 1190, of 150 Jews. And then we wind up on the steps of the female prison for Alice's piece de resistance: a re-enactment of the hanging of Dick Turpin.

This time, Alice picks on a male member of her audience, Sam Marchant, to play the part of the notorious highwayman.

Poor Sam and his fianceé Amanda had only gone to Treasurer's House to check it out as a potential venue for their wedding. They'd met Alice, and signed up for the tour. And here Sam was, standing on the steps, twitching and jerking to represent the last moments of a man on a gallows.

"Don't we like to see a man well hanged, eh?" asks Alice.

• The Treasurer's House Bloody Tour of York leaves from outside the Treasurer's House at 6.30pm on Wednesday evenings only for the next three weeks, on October 1, 8 and 15. Tickets £10, which includes a glass of mulled wine. More information from 01904 624247 or email