In the bomb disposal profession, the term‘ bad day at the office’ has an altogether different resonance.

Doug Napier remembers his bad day at the office well enough now for him to realise that it totally changed the way he worked.

“I lost the cowboy in me at that point,” he tells me of that day in Iraq back in 2003.

He doesn’t go into detail about what precisely happened back then. It’s almost as if by keeping it to himself, the moment retains its power as a lesson learned and an experience never to be repeated. His answers to my questioning though leaves no doubt that it was a touch and go moment.

“I made a series of bad decisions that left me wondering why I survived it, and it altered my operating principles from that day forward, “ the former US Ranger and infantryman tells me.

“I realised that it’s not safe to make assumptions, so it’s unfortunate that it took a close call for me to understand that, but now I’m very methodical, I think everything through before I do it, I think of the consequences, I think of all my options, I know my limitations,” he confesses, pausing briefly, before adding his final thought on the lesson of that close call.

“So today even a simple device with a pressure plate and a battery, I’ll spend two hours rendering that safe.”

Right now most of Doug Napier’s working days are spent in and around the devastated Iraqi city of Mosul.

It’s there for months now, that the Iraqi Army and Kurdish peshmerga fighters have been engaged in fierce fighting with Islamic State (IS) jihadists, as they try to oust the extremists from their self-proclaimed caliphate in Iraq’s second largest city.

From where Napier and I stand talking, Mosul, his workplace, is barely an hour’s drive away, as close as Glasgow is to Edinburgh.

When not in the field, Napier lives in a large sprawling house with huge grounds in the Iraqi Kurdistan city of Erbil.

This compound is the headquarters of the Optima Group, a British based company comprised mainly of former military Explosive Ordnance Disposal (EOD) experts.

For the foreseeable future their job under contract from the UN is to help clear the hundreds of thousands of landmines and improvised explosive devices (IED’S), IS jihadists have left in their wake.

In making safe key installations like electricity sub-stations, water plants, schools and universities, the aim is to re-establish some kind of functioning infrastructure in those parts of Mosul newly liberated from IS rule.

By any standards it’s a daunting task - not least because fighting continues in neighbourhoods in the west of the city and IS sleeper cells remain active in the liberated eastern part. The IED threat meanwhile is like a contagion across the whole of Mosul and beyond.

There is precedent here of course. In the wars that raged during the final quarter of the 20th century there was a surge in the use of landmines.

By the mid-1990s these indiscriminate and sinister weapons were killing something like 26,000 people every year. After the Ottawa Treaty that came into force in in 1999 however, the number of fatalities dropped.

Today though that trend is in sharp reverse in great part because of the deployment of IED’s by IS in Iraq and Syria.

Once again the numbers of those killed and maimed among the civilian population are making for a landmine and IED emergency not seen for decades, and experts agree it will take decades more to make any real impact in reducing the threat.

The journey by road from Optima Group’s headquarters to Mosul involves passing through checkpoints controlled by Kurdish peshmerga fighters, the Iraqi Army and their allies the Shi’ite militia Hashd al-Shaabi.

It’s a route I’ve taken in stages many times since last August when I first began covering the military operation to retake Mosul.

Passing along the Mosul highway, canyons of ruins flank the roadside where communities have borne the brunt of the fighting.

Last week while travelling with Optima Group disposal experts I once again passed the town of Bartella just east of Mosul, where last October I saw scores of landmines and IED’s newly dug up and defused by the advancing Iraqi Army’s special forces.

Today the threat of IED’s on the road itself is less, but in the fields and towns adjacent they remain a major threat, many sitting still undiscovered waiting to be rendered safe.

“Vehicle static right, IA with long left, truck merging from right,” comes the relay of security messages from the observer in the lead armoured Landcruiser of our four vehicle convoy as we head towards Mosul.

To the uninitiated it’s a strange lexicon with very serious significance.

A static vehicle for example might contain a remote controlled bomb that could detonate when we pass by. IA is shorthand for Iraqi Army as IP is the same for Iraqi policeman, while a ‘long’ means they are carrying a weapon like an assault rifle.

Uneven ground on the road could be the location of a roadside bomb while vehicles merging from lanes either side might be suicide car or truck bombers. As if to remind us of this, inside Mosul itself we pass a huge crater where only two days before an IS suicide bomber had blown himself and others up, but where now in a show of resilience, civilians had set up stall on the crater’s edge selling fruit and other commodities.

All the time during our journey our “eyes on” information is relayed between vehicles by a former British soldier called Ollie from Manchester, who is also a veteran private security contractor and Optima Group’s chief of security around Mosul.

Over the years Ollie has learned the hard way of the price that can be paid for working in such a hostile environment. In Baghdad some years ago a number of his colleagues were kidnapped by gunmen, while in another incident he himself was shot in the leg.

“My wife asked me how I managed to get shot in the leg, when all I was doing out here was training people,” he joked, never taking his eyes off the road ahead as we chatted in the Landcruiser.

Once inside Mosul, I was shown some of the IED sites on which Optima Group disposal teams are already working or will be working in the near future. Among the locations was a warehouse and the city’s university campus that sits ruined and is said to be littered with IED’s.

The scale of the task in clearing Mosul university grounds was put into context by one of the team, who compared the job with what they had found and had to deal with in the Iraqi town of Ramadi when it was liberated from IS in 2016.

In Ramadi’s university more than 3,000 explosive devices and booby traps had to be cleared in an operation that took a full year but was concentrated on very small area. Ramadi as a town is a fraction of the size of Mosul as is its university.

But it’s not just major buildings that have been contaminated by IED’s.

In Mosul’s residential neighbourhoods and in villages and towns around the city previously occupied by IS, civilians desperate to restart their lives are returning to find their homes, streets and fields riddled with bombs.

In this environment nothing is safe, a situation summed up by one disposal expert who described his working rule of thumb in spotting the

tell-tale signs of booby-trap devices as the “presence of the abnormal and absence of the normal”.

Anyone who has ever seen the critically acclaimed movie The Hurt Locker, about a US army explosive ordnance disposal (EOD) team during the previous Iraq War will instantly recognise the sinister and cynical nature of such traps.

Nothing in this lethal terrain can be presumed to be benign. A child’s football or doll, teapots, television sets, fridges, chicken coops have all been rigged with explosives, and even dead bodies are sometimes booby-trapped.

Disposal teams have found the most mundane objects set up in this way. Some have motion sensors or are fitted with anti-tilt and anti-tamper mechanisms on them so that those trying to clear or render them safe will themselves activate the explosion.

“The main thing is that there are a couple of components to an IED, you have an explosive charge, you have what might be called a switch, a thing that makes it detonate and you have power supply,” explains Doug Napier, as he shows me a small patch of training ground at the Optima Group compound in which are sunk a variety of mock IED’s of the type he and the team regularly encounter.

Among them are plastic jerry cans full of ammonium nitrate and linked to detonators. Then there are pressure plates that are triggered by someone stepping on them that are sensitive enough to be detonated by a child but big enough to blow up a tank. Some are incredibly sophisticated others less so like a hand-grenade with its pin removed and placed in a glass balanced on top of a door.

Then there are crush wires, small stands of wire that resemble a string of Christmas fairy lights but are thinner and coloured to blend in with the earth. Instead of lights though these have tiny taped circuits that when stood on trigger a blast that can occur just feet or hundreds of yard away. Crush wires are near impossible to see when strewn on the ground in the likes of Mosul’s rubble strewn streets.

“The main charge that I’ve seen since being here are primarily improvised explosive, so basically they will take industrial chemicals or the type of stuff you would use on a farm or other non military environments and adapt it into an explosive,” says Napier.

The other explosive IS use say disposal operators are repurposed military stock and the third are IED’s the jihadists manufacture themselves on a factory scale.

“They even have their own quality control labels,” says Optima Group’s technical specialist Mark Warburton, another former soldier whose knowledge of the myriad devices IS use is encyclopedic.

So organised is IS’s production line that Napier says, he can look at the parts and recognise when they have come from the same manufactured stock.

“I can look at the parts and tell those that came from the same batches as the taping might be wrapped the same way,” says Napier.

“Then you can tell that on other days they were clearly working from the same instruction sheet but had a different supplies for different components, so there is a lot you can learn just by looking at the bits,” he continues.

As if the task of rendering safe these devices was not difficult enough one of the jobs the disposal teams are doing is also trying to preserve the forensic evidence that might through DNA or other testing help identify the bomber.

“Defeating the device and making the place safe is one thing, but this potentially enables us to find the bomber and make the wider community safe," says Napier.

“We are funneling the evidence into the law enforcement community so they can chase down the bad guys, but my main job remains just dealing with the bad guys handiwork,” he says.

For now dealing with that lethal handiwork has taken on a new urgency in Iraq.

The United Nation’s body on action against landmines (UNMAS) has estimated the cost for removing landmines and explosives from Mosul alone will be $50 million, this on top of the same amount for the whole country.

For now though it is the human cost that really matters. The number of fatalities and casualties is growing daily and will continue to do so. As one EOD operator put it, the war of attrition against the civilian population that these bombs is responsible for is truly “horrific”.

“Go into a school that is functioning again and the walls are covered with the photographs of children who have been their victims,” he told me.

For long into the foreseeable future the ‘presence of the abnormal’ in the shape of IED’s along with the appalling pain and suffering they cause will continue to plague the people of Mosul.