Simply because they are not expected, ghosts that appear in modern surroundings and with no warning often feel like the most terrifying of all.

Fog-circled ruins, ages-old castles, dark, foreboding houses – these are the hunting ground of the ghost, not a shared office where the biggest issue is unpaid volunteer workers pinching lightbulbs to use at home.

We expect ghosts to be chain-clanking, cemetery haunting, storybook floating white sheets that groan or period-dressed ladies and gentlemen returning to right a dreadful wrong.

But sometimes, the things that come in the night are shapeless and invisible, black vortexes of misery that cloak us in darkness darker than the dead of night – and they can appear anywhere, at any time, to anyone.

Our story takes us to one of Norwich’s busiest thoroughfares in the heart of the city: Exchange Street.

Weird Norfolk’s job is to collect and collate the unusual and unexplained, to bring the county’s folklore back to life and to listen when people share their unsettling stories.

Over the years, patterns emerge, stories are told to us about the same places from people who have never met but whose experiences are startlingly similar.

We have received four tales about Exchange Street, all varying very slightly, some more unnerving than others, from the same area which has played many roles in Norwich’s history.

This was where Duke’s built palaces, where the river ran red like blood from the rose madder dye used by the textile industry, where cellars were always flooded, an area which author Thomas Baskerville visited in 1681 and declared “…a dung-hole place”.

It is also where something very strange happened to reader Martin.

He told Weird Norfolk of an unsettling episode which happened when he was working on a magazine produced by the Norfolk Friends of the Earth.

At the time, the charitable organisation was based on Exchange Street close to where it meets St Andrew's Street, part of a row of buildings which all share a secret hidden in plain sight. But more of that, later.

It was the 1990s and Martin and other unpaid volunteers regularly worked night shifts.

“We often crawled into work around late afternoon and worked through the night,” he explained.

There were rumours about the office space which he had heard from others who had worked in the building at night: disembodied footsteps that appeared from nowhere, banging that could not be explained, strange noises that couldn’t be accounted for.

But it was an old building, old buildings creak, the road outside was busy, there are always a list of excuses as to why strange noises happen, most of which involve the paranormal.

On late shifts, a trip to the kitchen in order to make a hot drink involved walking along a 10ft windowless corridor from the office. It was unlit – the lightbulbs had long-since disappeared.

Martin said: “One night I was 'hit' by what I can only describe as a wall of misery in the unlit corridor. The dark was even darker where this 'thing' was.

“It was like a damp sheet of very black space wrapping itself around me, with the aforementioned misery and overwhelming sadness and fear condensed into a few seconds.

“I headed very quickly to the safety of the kitchen at the end of the corridor and spent a long time there before I had the guts to head back through it to get to the office.”

Exchange Street takes its name from the Corn Exchange developed there in 1828 and redeveloped in 1868: it was a place for farmers and dealers to strike bargains and also a venue for socialising.

Earlier still, it was the site of a church, St Crowche’s, which was built before 1272 and desecrated and mostly demolished in 1551, and its graveyard, which used to be an important part of a pilgrimage to Norwich.

Pilgrims would come to visit the graves of Adam and Botild, the parents of Bishop Gilbert of Hamar, who was born and died in Norwich but who travelled to Shetland and Norway during his remarkable career which ended with his death in 1287.

Those who visited the grave and prayed for the couple's souls were said to be given 300 days of pardon from God.

This was also the area close to one of Norwich’s most notorious workhouses which was based in the nearby repurposed Duke’s Palace (on the site of today’s car park).

Prison reformer James Neild wrote about the insanitary conditions at the workhouse that was just feet from what is now modern-day Exchange Street in 1805.

“The appearance of the poor was singularly squalid, dirty and miserable and their clothing ragged and wretched,” he wrote, adding that the sick lived with the well, causing the spread of killer infections such as smallpox.

He was also horrified that a 12-year-old boy was forced to wear an iron collar “…with four projecting prongs, secured by a large clumsy padlock” along with a leg iron to which was secured a log which was 2ft 7inches and weighing 22lb.

The boy wore his torture implement by day and night.

Martin is unsure what happened on that night 30 years ago, but it has stayed with him.

“It was just so odd,” he said, “plenty of people heard things, the noises were a common occurrence, but nobody I know who was around at the time actually saw anything. I was unfortunate enough to get the full misery phenomena!”

Weird Norfolk contacted the current occupants of the building in question, and another previous tenant, but no one had seen or heard of anything unusual.

However: we have received four stories, including Martin’s, about Exchange Street – one from a member of staff from a former hairdressing salon and two from another business based there.

“There are stories about lights turning themselves off and on and of footsteps being heard when no one was there,” said the man, who did not wish to be named.

“Things would be moved and laughter would be heard. Sometimes you’d hear older children in the building but there were none there. It never felt evil or malevolent, just a bit cheeky. People I worked with weren’t afraid.”

Many of the buildings involved share a wall with one of Norwich’s vanished churches, St Crowche’s, which was built before 1272 and desecrated and demolished in 1551.

In August 1834, workmen excavating at the lower part of the west side of Exchange Street found a number of human skulls and bones at the site of the former church.

And when a famous city pub, The Hole in the Wall, was demolished four years later in order to build the present Exchange Street, it was discovered that it had been built within the old church’s chancel.

"We all knew about the ghosts in the building," a reader who worked on Exchange Street told Weird Norfolk, "you heard them mostly at night, when it was quiet. I only felt frightened once, and that was when I went upstairs. I was fumbling for the light and as I did, I heard someone breathing.

"I made sure not to be alone there at night again."

The stones in the wall of the building to the left-hand side of the alley that runs behind them are the only visible remains of the church that once stood here: and there, if you look carefully, are the remains of a stone corbel carved with a face.

Oh the things it has seen. The stories it could tell.

* Do you have a story for Weird Norfolk? Email stacia.briggs@archant.co.uk