Emma LeeAs Halloween approaches, City tour guide Mistress Jude lets us in on some of the spine-chilling secrets of Horrid Norwich.Emma Lee

Who is the mysterious Mistress Jude? Why has she summoned me to the Erpingham Gate of Norwich Cathedral? And how will I recognise her?

Hmm, the fact that she's dressed from head to toe in black and has a skull dangling from a string in her hand - at 10 in the morning - is a little bit of a giveaway.

Mistress Jude - AKA Jude Sayer - is one of Norwich's blue badge tour guides. And this week she and her colleague, Mistress Ann, will be leading special half-term tours of the city.

Because Halloween is approaching, the historical walking tours, which take in some of the city's best-known landmarks, have some extra added grisliness - and I'm being given a sneak preview of what's in store.

But before we set off on our Horrid Norwich tour, some introductions are in order. Jude's companion, it turns out, is Martha Sheward. The Victorian woman met a gruesome end at the hands of her husband, pub landlord William. He managed to pass off her disappearance with an innocent explanation. But then body parts started appearing around the city…

Having avoided detection for almost two decades, William eventually handed himself in to the police and confessed to his wicked crime. But Martha's head was never found - and William never let on what had happened to it.

While Norwich's quaint cobbled streets might be a magnet for tourists and their cameras, there's some gruesome secrets from the past lurking behind those photogenic facades.

And tragic Martha's story is just one of the many tales of skulduggery from the city's not-so-fine, seedy side that Mistress Jude and Mistress Ann will be revealing.

Rebellion, witchcraft, plague and murder most foul - the tour has it all. Fittingly, as the spookiest day of the year is almost here, there are also some spine-chillers - including the story of Father Tunstall.

Hung drawn and quartered for his religious beliefs in the 17th century, his ghostly figure was sighted by a guest at the Maid's Head Hotel in Tombland more than 100 years later.

The tour includes the cathedral grounds, plus stops at the city's oldest watering hole, the Adam and Eve, Bishopgate, Fye Bridge (where women who were suspected of witchcraft faced a drenching courtesy of the ducking stool) and Tombland, which although it sounds like an apt name, actually means 'an open space'.

The programme is made up of afternoon tours, which set off at 3.30pm and which have been toned down to make them suitable for all children apart from the very young or those of a sensitive nature. The after-dark tours, which start at 6.30pm, are aimed at adults - the 'director's cut', with none of the gory details spared. Both children and the young at heart are encouraged to get into the spirit and dress up - and there will be a prize for the best costume.

Jude says: 'This is a fascinating tour around the more macabre side of Norwich. It's a really great chance for people to learn something new about the city. We've organised it over half-term so families can come along, or groups of friends can get together and make a night of it.'

The history of some of the city's most stunning buildings is brought to life by Jude, who is a master storyteller. Without wanting to spoil any surprises, there are some places you may never look at in the same way again.

'I tell people that the most horrifying thing of all is that at one time the council wanted to demolish Elm Hill as part of the slum clearances,' laughs Jude.

Jude - who cites the free-thinker Harriet Martineau and Dr Rigby as her favourite characters from Norwich's past - describes herself as a 'history fanatic'.

Leading city tours is about much more than reciting facts and dates parrot-fashion. You have to make them colourful and engage visitors. And with performing in the blood, it's little wonder that Jude is so accomplished at it.

'My parents were both on the stage. Father was a singer and mother was a dancer,' she says.

But she became a blue badge guide almost by accident.

'I moved to Norwich and someone said 'there's a course you might like'. I thought I was signing up for a 10-week evening course,' she says.

It turned out to be a training course for tourist guides. Not only does Jude cover the city, but the rest of the county too.

'It was actually an NVQ level four with exams and assignments. I was delighted but taken aback that that was what it was,' she says.

Children's tours are being held at 3.30pm from today until Halloween. Adult tours, which set off at 6.30pm, are being held from Wednesday to Saturday. Both last approximately an hour. Tickets cost �5 (�3 Go4less card holders) and are available from the Norwich Tourist Information Centre at the Forum. For further details phone 01603 213999.