Clerkenwell’s House of Detention occupied the site of a previous jail dating back to the early 1600s – although the 9,000 sq ft of tunnels, vaults and cells date from the 1840s.
For more than 45 years ‘the dench’ as it was known operated as a remand prison for those awaiting trial. Around 10,000 accused passed through its gates annually on their way to the neighbouring Middlesex Sessions court.
The site in Sans Walk was damaged by a terrorist bomb in 1867 when Irish Fenians perpetrated what was known as the ‘Clerkenwell Outrage’.
They blew a hole in the prison wall, but the warders had been tipped off and the inmates were not in the exercise yard.
But the blast destroyed nearby tenement houses, killing 12 and wounding 120 – and ringleader Michael Barratt became the last person publicly executed in London, on gallows outside Newgate Prison.
The House of Detention was demolished in 1890 and Hugh Myddleton School was built on the site.
But the underground part survived unused until it served as a shelter during the London Blitz.
In the 1990s it became a rather creepy museum offering tours of the underground passageways which include the former female corridor of brick walls and arches and stone floors with cells off either side of the passage.
Some have metal window grilles or cast iron “eyes” for chaining up prisoners – while there’s also a former warder’s hall and office with granite columns and cast iron beams.
It’s from this time that reports of ghostly sightings sprang up after visitors caught sight of a shadowy figure moving through the darkness, or heard the sobs of a little girl from inside the jail.
Others returned from the cells asking about the old lady who seemed to be searching for something but disappeared when they spoke to her.
The prison featured on an episode of Living TV’s Most Haunted and late night ghost hunting tours of the tunnels could be booked.
Above ground the Victorian school closed in 1971 and is now Kingsway College Clerkenwell Centre.
But below ground the Grade II listed vaults have lain empty since 2000 when the museum closed down.
They have proved a suitably atmospheric backdrop hired out for events and filming ranging from the Robert Downey Jr Sherlock Holmes in 2009 to Spooks, St Trinian’s 2 and The Secret Diary of a Callgirl.
But they were added to English Heritage’s “at risk” register in 2023 with their condition described as “slow decay”.
