Edinburgh’s Old Town is a warren of towering tenements and narrow alleys.

These appear picturesque today, but they were built with a different purpose in mind - personal safety. Scotland was a dangerous place in the late Dark Ages, and the city’s fearful inhabitants chose to live close to the castle’s walls. As a result, they built up rather than out.

Many of these ancient high-rises are still standing today. But modern plumbing and central heating have erased reminders of what life was really like for those who lived in them five centuries ago.

Ironically, it was the construction of a new building - the Royal Exchange - in 1753, which preserved part of the Old Town in its original form. To clear the site, the authorities demolished the upper stories of the houses, but left the dwellings below street level to serve as the foundations of the new building - now the City Chambers. This group of dwellings has been dubbed Real Mary King’s Close.

The tour of the Close begins in a wood-panelled room in the City Chambers.

You step through an unassuming door, and back into 16th Century Edinburgh.

The guide is in character; we were shown around by Agnes Chambers, a housemaid in the year 1535. All the characters and stories used on the tour are based on real people and events, thanks to records dating back to the reign of Charles I.

Ms Chambers tells us to watch our step on the medieval flooring with its slopes and unexpected obstacles. Then she sets off into the narrow close, once open to the sky but now obscured by the more modern building above.

She takes a sharp right into the first dwelling - which gives a glimpse into the room of Mary King. Mary was the close’s wealthiest resident, which is why it is named after her. As such, she would have lived on the top floor where light and fresh air were more abundant.

By contrast, those on the lower levels lived in permanent gloom because the dwellings were built so close together. They also had to endure the stench of the excreta tossed from chamber pots from the windows above (the holler - “Gardy loo!” - served as warning of what was to follow.) My seven-year-old companion is fascinated by the grimness of life in the lower dwellings. Families of up to 20 lived in raw, bare rooms with no running water, electricity or proper sanitation. “Makes you glad you’ve got a toilet,” he remarked. I’ll second that.

The bubonic plague, which hit Edinburgh in 1643, killed off half the city’s population of ????. Among the victims was the family of gravedigger, John Craig, who are portrayed in one of the rooms we visit. Mr Craig himself lies dead in a corner. Doctor George Rae attends to his wife and three sons. Dr Rae, dressed head to foot in thick black leather, his face covered by a beaked mask filled with sweet-smelling herbs, looks like the grim reaper as he lances an infected boil with a hot needle.

Legend has it that plague-infected families were left to die when the city authorities bricked up Mary King’s Close. We learn that this is untrue. In fact, the council, and local people, were more progressive in their treatment of the disease. The family would have confined themselves in their room to further infection, living on food left at the door by neighbours until they could be moved to quarantine on the outskirts of the city.

The Real Mary King’s Close is not for the faint-hearted, and is unsuitable for under-fives. My young co-reviewer admitted that it was a bit scary even for someone of his advanced years. But the gruesome tales and creaking doors are more thrilling than chilling.

Education at the close

The Real Mary King’s Close is planning to introduce several curriculum-based tours next year. The present tour is already valuable for showing the diversity of past lifestyles, the changing character of settlements, and chronological development.

Mini-versions of the guides’ costumes are available for children to wear when they go on the tour.

The Real Mary King’s Close, Warriston’s Close (adjacent to the City Chambers), High Street, Edinburgh. Tel: 08702 430160; www.realmarykingsclose.com. Opening times: April to October, 10am - 9pm; November to March, 10am - 4pm.

School groups of 15 or more: pound;3 per person (one free teacher per 10 pupils).

Free previews are available for teachers who are considering a class visit.