Deep in the bowels of Bradford's most imposing civic building are a reminder of its grisly past.
From 1873 until 1974, Bradford's main police station was based inside the gothic City Hall. Hundreds of murderers passed through here, as well as innumerable other common criminals, and the great escapologist Harry Houdini managed to break free from the jail in just 20 minutes during a publicity stunt in 1904.
This is what it's like to work as a tour guide in Yorkshire
Today, the cells, courtroom and parade room are open to the public as the Bradford Police Museum, a sometimes-ghoulish visitor attraction which opened in 2015 and has since become one of the city's hidden gems.
They're so well-preserved that they regularly appear in TV period dramas, including Peaky Blinders and Agatha Christie's Poirot mystery The ABC Murders. The custody suite has also featured in Emmerdale and the upcoming spy thriller Official Secrets, which stars Keira Knightley.
The museum's volunteers - most of them retired police officers - are now preparing to host candlelit ghost tours to celebrate Halloween.
After-hours visitors will be able to see the cells in darkness and listen to stories of City Hall's resident poltergeist, Chains Charlie - a burglar who was reportedly tortured before being executed by infamous hangman James Berry in 1888, and is said to haunt the old nick.
The Yorkshire sheep farm that became Britain's highest vineyard
The collection of memorabilia on display in the old parade room includes an old Velocette 'Noddy' motorcycle, Victorian truncheons and other artifacts spanning 150 years of law enforcement in Bradford.
Former police inspector Martin Baines now manages the museum and considers the ghost tours to be a highlight of the events calendar.
"We get about 5,000 visitors a year now, which is good to say we're only open two days a week between March and November. People love it - it's a real hidden gem.
"We offer guided tours, and we've laid the courtroom out as it would have been in about 1900. We take people up the dog stairs that led from the cells to the court.
"We've had visitors from all over the world, as well as lots of local people."
The museum tells the story of Bradford's pioneering police force, which was the first outside London to use fingerprint evidence to secure a conviction, the first to use a taped murder confession in court - it was recorded covertly in the City Hall cells - and the first to use colour photography in the 1930s.
"The ghost tours are very popular. It's a really different kind of visit - one of our guides did an investigation into the poltergeists at City Hall, and we tell the story of Chains Charlie by candlelight in the courtroom. Quite a few of the visitors in the past have seen paranormal activity and even filmed it, although I've never come across anything myself.
"There were a few notorious prisoners - all of Bradford's murderers from 1873 onwards would have been held here, but most never came back to Bradford after they'd appeared in court.
This Yorkshire railway tunnel has been named as one of Britain's most endangered buildings
"During World War Two, a Nazi bomber was shot down over Idle and the crew bailed out and were arrested. They were brought here before being taken away to POW camps.
"We have a lot of Peaky Blinders fans visiting, and that's something we want to promote more - the publicity from the filming has been fantastic."
Bradford Police Museum staff are currently recruiting more volunteers to help run the attraction and manage the collection. They're looking for tour guides, meet-and-greet/shop assistants, curators and people with vehicle maintenance experience to help care for their fleet of two vintage police cars and five motorcycles. Email email@example.com to express your interest.
The museum is open on Fridays and Saturdays until the end of November, and will re-open after the winter break in March. The next ghost tour is on October 31 and tickets can be booked online.