The number of deliberate fires being set across Lancashire is rising - and most arsonists get away with it.
Some 828 arson attacks were noted by police last year, up from 790 in 2017 and 680 in 2016, figures obtained by The Gazette showed.
But just 112 people were arrested - up from 101 in 2017 and 102 in 2016.
Most cases were closed because officers had "no line of enquiry" to chase, data released under freedom of information laws revealed.
In a statement, Lancashire Police said: "We take all reports of arson seriously. It's a senseless and dangerous crime and where it's clear a fire is not accidental we will do what we can to ensure we bring offenders to justice.
"Businesses and communities can take their own measures to reduce the risk and protect their homes and premises. Taking time to dispose of materials safely will ensure that opportunists are unable to cause damage and disruption to lives and businesses."
Preston has suffered at the hands of firebugs more than anywhere else in Lancashire in the past three years, with a total of 422 arson attacks reported.
There were 295 deliberate fires in Blackpool, and 240 in Blackburn in the east of the county.
As well as a lack of leads, which led to the closure of 1,670 cases in the same period, other key reasons for a lack of arrests included "evidential difficulties", which meant 263 cases collapsed.
Despite having a suspect in mind, officers decided further investigation was not in the public interest 42 times.
Suspects were too young to prosecute - the criminal age of responsibility is 10 - nine times.
And they were judged to be too poorly, mentally or physically, 18 times.
On one occasion, a suspect died before they could be arrested.
Cautions were handed out seven times, 108 people were charged or summonsed, and 52 were given community resolution orders, where the arsonists admit their guilt to avoid a criminal record.
Youth cautions were also handed out 10 times.
Around 10 per cent of house fires in Lancashire were started deliberately, it was reported last year, though the figure had dropped from 11.7 per cent in 2016/17.
"This includes those where someone sets the fire in their own dwelling," a spokesman for the Lancashire Fire and Rescue Service (LFRS) said at the time.
"Since 2013, five people have been killed in fires started deliberately in Lancashire – this includes those who started the fire themselves to commit suicide.”
Dave Green, of the Fire Brigades Union, added: “Starting fires deliberately in the home is a heinous crime. Arsonists do not just put the immediate victims at risk – they put whole communities and firefighters themselves in jeopardy.”
One of the most high profile arson attacks, which remains unsolved, is the one that claimed the life of 96-year-old Edith Stuart.
She died in October 2010 after suffering 50 per cent burns when someone held a flame to her bedding at the Cleveleys Park Care Home.
Two people were arrested on suspicion of murder but, two years later, the Crown Prosecution Service ruled there was insufficient evidence to take the case any further.
Nobody has ever been caught, and her daughter Shirley Fish, 82, of Poulton, said: "I hope the people who did it realised just how awful it was and tried to change and become good citizens.
"My mum must have been terrified because she could not get off the bed. For somebody to set fire to it when she could not get off, it must have been horrific.
"It's something that never leaves the family."
When asked what she thinks of people who deliberately start fires, Ms Fish added: "My only reason is they must be a little bit sick and things are going wrong for them, let's put it that way.
"Then horrible things happen. There's so many, it's just constant. It will never stop."