On Christmas Day 2017, a traffic police officer's life began slowly to unravel after he was injured during a pursuit. Two years later he underwent surgery and was told he could no longer do the job he loved. His mental health took a nosedive but he found solace in his long-time hobby - photography.
"As a traffic officer I saw things no-one should see," Det Sgt Colin Shead says.
"Now I see things I want everyone to see."
Here, he speaks candidly about his mental health, and shares some of the images that have helped him cope.
'Like a lifeline'
The 51-year-old officer has clocked up more than 30 years on the force, joining Essex Police's roads policing unit (RPU) in 2010.
"I'd always wanted to do traffic work, because I wanted to protect people from harm on the roads," he says.
"When you start, there's the great thrill and excitement of flying around all over the place - then you get the serious side - and the fatalities.
"You're the first at the scene when someone's been killed - you see that first-hand and it takes its toll."
After his knee was injured in 2017, he kept working, afraid he might lose the job he loved.
But after surgery in March 2019 he was told he could no longer be operational - he would have to take a desk job.
"In June that year, everything came to a head. It was breaking point," he says.
"Everything came out - everything I had held inside."
Det Sgt Shead was diagnosed with post-traumatic stress disorder (PTSD).
His PTSD was the result of a combination of factors - losing his role in roads policing and the traumatic things he had witnessed and experienced on that job, he says.
"I would get intrusive thoughts, and flashbacks.
"There was a particular scene from a fatal accident where a teenage boy came off his motorbike, hit a tree and he died.
"The boy's father lived nearby and came running over - he fell to his knees in front of me - and then he just picked up his son's crash helmet and threw it away."
The scene would "play over and over again in my head", he recalls.
He credits his friend and mentor, wildlife photographer Russell Savory, with "saving" him.
Photography and filming became "like a lifeline".
"When you're out there, it's a complete focus, you concentrate on the subject matter - you can spend four or six hours on a subject for just one minute of film."
Photography has become more important as the years have gone on.
"There is no life outside of your lens. There isn't. Your focus is on what you are looking at or looking for."
The death of his grandfather in 2016 was one of a number of tipping points he had been pushing to the back of his mind.
"I was with him in hospital when he died.
"I was in my uniform - I saw my uniform as something that protected people - but it couldn't protect him.
"I lost faith in my uniform - it was like a wake-up call that we're not superheroes."
Looking back, Det Sgt Shead says his illness was almost inevitable.
"I remember back in 2018 hearing about a fatal [accident] on the A12, and just thinking, 'please, not another one'.
"I had to have my uniform burned after attending. I couldn't get the stench of death - from the scene - out of it.
"I thought I'd put this to bed, but it was one after another, after another, it was becoming endless.
"I became aware of my own mortality - driving at high speeds."
Taking pictures is the complete opposite, he says.
"It's about sitting and waiting for things - nothing but you and the elements and nature.
"No distraction. Nothing."
Det Sgt Shead is far from alone as an officer with PTSD.
The Police Federation - which represents more than 130,000 rank and file officers in the UK - says the numbers suffering with mental health conditions have soared.
Figures published last month show 13,263 officers were absent due to stress, depression, anxiety, or PTSD in the past financial year, compared with 8,450 the year before - an increase of 57%.
"One in five officers have PTSD, and an overwhelming majority have experienced a traumatic incident at some point during their career which undoubtedly has a significant impact on their mental health," the federation's head of wellbeing, Sue Honeywill, says.
The numbers are likely to be higher as the figures do not include civilian police staff such as crime scene investigators.
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Essex Police says providing support to its staff is "a responsibility we take very seriously".
Its Trauma Risk Management (TRiM) practitioners provide help to officers and staff following a traumatic event and identify those who may be at risk.
Managers, the force says, are trained to identify when an officer or staff member may need help and an occupational health team and employee assistance programme give access to support, counselling and other services.
Officers and staff returning to work following a period of absence are supported through recuperative duties and ensuring reasonable adjustments are in place, so their working environment reflects their needs.
Figures for Essex Police at the end of March this year show 180 staff were on recuperative duties and 211 on adjusted roles.
After surgery in 2019 Det Sgt Shead had some time off.
It gave him, he says, "time to reflect, to stop and think and unwind".
"The trigger came during this time," he says.
"On 15 June 2019, I just found myself shaking - holding onto the bathroom sink, looking in the mirror and thinking, 'this isn't right'."
Essex Police's counselling and wellbeing team stepped in, and he was diagnosed with PTSD.
"I went through a period of counselling, therapy and medication - it was really painful for me."
He had six months off work.
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"I was told it was classic PTSD and in a way it was a relief having it labelled.
"I was burning myself out, and I hadn't realised."
To be told he could no longer function as an operational roads policing officer was a shock.
"My world collapsed," he says. "I didn't join to be behind a desk.
"This has taken what I thought was my lifetime career, away from me.
"My mind says that at the drop of a hat I'd do [roads policing] again, but, being honest, enough is enough."
For the past three years he has had a desk-based position working with the case investigation team dealing with anything from road rage to theft.
"I do enjoy what I do. I learnt a lot in those six months off - that you have to look after yourself, or you're no good to anyone.
"I think I'm now honest with myself."
So, what is life like, now?
Det Sgt Shead appealed against restrictions placed upon him by the force's medical advisor that took him off operational work.
He was successful and went on to pass his job-related fitness test.
In September this year he was deployed to Operation London Bridge, on duty as the Queen's coffin was taken from Buckingham Palace to the Palace of Westminster.
"Knowing I could go back out there if I wanted to, has made a huge difference," he says.
"But I'm happy - genuinely happy - and mentally, I'm good."
Getting out and about with his camera has played a large part in that.
"If you're prepared to wait, then eventually everything will fall into place when it comes to wildlife.
"It may take a few years but you'll get there eventually."
Speaking about one of his photographs of the sun rising over the sea at Dovercourt, taken in April, he says: "One thing Russell [Savory] taught me is that if you want to get that shot, you have to get up early.
"Some days I'm up at 03:00 to photograph the sunrise, or take pictures of beavers.
"Life is short, the day is long. Make the most of it while you can."