"Mistakes" in the redesign of a city centre station led to the rapid spread of a huge fire. BBC News Online asks what went wrong.
Five years ago, amid great fanfare, Nottingham railway station's £60m refurbishment was opened.
The work, which was carried out by Network Rail and East Midlands Trains gave the Grade II-listed Edwardian building a striking new entrance with a light, airy feel, with extra space for its ticket office and shops and improved parking.
But less than four years later, it was filled with thick smoke due to a fire that raged for 12 hours and caused £5.6m of damage.
At Nottingham Crown Court on Tuesday, Gemma Peat, 34, was jailed for 25 months after admitting arson.
The court heard Peat entered the ladies' toilets in the new-look station at 05:31 GMT on the morning of 12 January 2018 and set fire to a sanitary bin after taking drugs.
From there, the fire rapidly spread through voids behind the stud walls of the new construction. It spread to the roof and reached the wooden bridge that takes passengers to their platforms.
Firefighters were able to stop it from reaching the platforms.
But how was the blaze able to spread so rapidly? And is there a risk of similar fires at other British railway stations?
'A flaw in the design'
Network Rail admits there was a "flaw in the design" of the station - namely a gap - or "void" of several inches between the ceiling and roof above the ladies' toilet, which was part of the 2014 refurbishment.
This redesign - in which a new front entrance was joined to the older platform area - resulted in what the fire service say was a "complex construction" where fire could spread.
In court, prosecutor Grace Hale said: "The wall that supported the public toilets should have had a compartment that would have provided 60 minutes of fire containment but it didn't extend all the way to the metal roof. There was a gap.
"That enabled the rapid spread of the fire."
'Accident waiting to happen'
The court was also told the station's builders had "cut corners" by packing the wall supporting the toilet block with a foot of highly flammable polystyrene after realising the ceiling was uneven.
Defending Peat, Adrian Langdale said: "If the correct material was used by Network Rail, the fire would not have spread within those few minutes.
"It just wasn't a fire-proof or fire-retardant ceiling, given how quickly it burned.
"It was an accident waiting to happen and it just so happened it was started by Miss Peat and her actions caused the fire. It could have been anyone."
Network Rail says the polystyrene has now been removed.
"The gap between the wall and the ceiling shouldn't have been there but that has since been rectified," a Network Rail spokeswoman said.
The body - which manages and repairs Britain's tracks and infrastructure - says the voids were "not a significant factor" in the spread of the fire. "It only sped things up by an hour," she said.
However, for the firefighters these voids certainly proved a hindrance in allowing them to tackle the flames.
"The fire burned continually through those voids which put it out of sight, making it incredibly difficult for us to locate," John Mills, group manager, said at the time.
"We couldn't physically see the orange flames we were trying to fight."
The service used thermal imaging to trace the flames and sent more than 100 firefighters to tackle them.
"It was an incredibly demanding incident," said Mr Mills.
"I've got firefighters than have served 20 plus years who said the heat they were exposed to was the like of which they had never experienced before."
In addition, the fire service said there were no sprinklers going off in the building that could have halted the blaze.
Nottinghamshire's incident commander Bryn Coleman has previously told the BBC that sprinklers could have limited the damage.
He said: "I don't believe there are any sprinklers in the building.
"If it had been a fire contained to the toilet block you would be looking at probably an hour [to put it out]."
Sentencing Peat, Judge Gregory Dickinson said those responsible for building the station had made "mistakes" in not fitting smoke alarms or sprinklers in the toilets.
Network Rail said the sprinklers were a "red herring". "They were not part of the building regulations," said a spokeswoman.
At the time, the city council - which helped to fund the initial refurbishment via £12m from the city's workplace parking levy - said fire safety advice was followed in the building's £60m refit.
"The project was managed by East Midlands Trains and Network Rail [and] the appropriate safety standards were met."
'A perfect vortex'
But how likely is such a blaze to happen again?
In court, the station's wooden "dispersal" bridge in the original listed part of the station was described as a "perfect vortex for the fire to spread".
Chris Milner, the editor of Railway Magazine, said: "From what I recall, it was a combination of the wooden structures, lack of sprinklers and roof voids that came together," he said.
"The station dates from 1904 and, although it was refurbished in 2014, it contains a large area behind the main concourse which is wood panelling and wood flooring.
"I also suspect there are challenges when modifying historic buildings to meet the latest fire regulations, but it's not a regular occurrence for someone to set fire to a toilet.
"As for whether this could happen again somewhere else, it depends.
"I would suggest there might be an issue with some of the Victorian stations with a high percentage of wood in their construction.
"Modern stations tend to be of brick, concrete, tiles or steel and glass construction so are more resilient to fire."
Network Rail said: "During the repair work we have installed fire breaks in the structure to give extra protection [to the wooden bridge]."
The judge in the case said station staff should have been quicker in raising the alarm and need to have a procedure in place.
A Network Rail spokesperson said the body had "learned a number of lessons" in the aftermath of the fire, following an internal investigation.
It said it had delivered a "significant package of improvements to the station building fabric" - including the installation of smoke alarms in the toilets - and could "provide reassurance that the recent work has improved the resilience of Nottingham station for the future".
When asked if there was a chance of a repeat of such a blaze - either at Nottingham or at other stations - a spokeswoman said "absolutely not".
"The building is now fully compliant," she said.
Sprinklers, she said, are still not a part of the building's design as they are not required by building regulations.
But for the fire service, they remain a concern.
Bryn Coleman, area manager at Nottinghamshire Fire and Rescue, said the lack of sprinklers in public buildings was something his colleagues had raised nationally.
"Sprinklers limit the fire spread," he said. "[They] undoubtedly save lives and limit fire damage but there is an impact in terms of impact and cost for businesses in terms of fitting them."
- 13 August 2019
- 17 January 2018