Behind the scenes of the prison system’s ‘SAS’, the National Tactical Response Group is on the front line of every riot, hostage crisis and rooftop protest in our jails

MARCHING through flames, heads down and riot shields up, they fearlessly fight on as more petrol bombs land around them.

Moments later, their German shepherd attack dog locks its jaws on an armed assailant and takes him down.

Welcome to the world of the prison system’s SAS, as The Sun becomes the first media organisation ever to be invited into the heart of the National Tactical Response Group (NTRG) in its 30-year history.

The elite unit is on the front line of every riot, hostage crisis and rooftop protest in our jails.

Today, at least, the carnage they are facing is part of a training exercise.

The force is so secret its very existence is barely known.

Clad in black combat gear, until today there were no photos of them in action.

However, we are not allowed to reveal their identities over fears they would be targeted by the violent criminals, including convicted terrorists, they are hired to confront.

Despite their appearance, none of the 41-strong NTRG unit is a police officer.

Every member, including its only female, has been hand-picked from the cream of the Prison Service.

They wear flame-proof uniforms, stab-proof vests and armoured gloves and go equipped with pepper spray, smoke bombs and batons.

Each is also highly trained in disciplines including methods of entry, working at height and hostage resolution.

Training is so tough that NTRG chiefs only regard new recruits as truly up to scratch after SEVEN years in their ranks.

Based at two regional HQs, each in secret rural locations, the NTRG is the first port of call in a jail crisis.

It was they who brought HMP Birmingham back under control in December last year after 500 violent lags went on the rampage across four wings, causing £6million damage.

Its officers were pelted with pool balls and attacked with paint.

But working cell to cell, they stamped out the worst uprising seen in an English jail in three decades within hours.

The NTRG’s work saw five inmates last week handed extra sentences, totalling 36 years for prison mutiny.

More recently it dealt with inmates taking other prisoners hostage after building barricades.

We were given the first public glimpse of the NTRG’s work during a day-long training exercise at the unit’s main HQ.

At first glance, the sprawling site looks like a dull industrial estate.

But inside each hangar lies a painstaking reconstruction of the jail landings, exercise yards and cells faced by the team in the field.

Our visit saw elite officers putting so-called “Tornado” teams — regular prison officers at local jails trained in riot control — through their paces.

When a riot such as Birmingham unfolds, Tornado officers are called out and answer to the NTRG.

It is the NTRG that plans the strategy, plots each move and leads the operation from the front line.

As Prisons Minister Sam Gyimah looks on during training, the teams march into one building, the floor covered in burning debris, as instructors play the roles of rioting lags.

Next, they see Prison Service dog handlers in action.

The instructor, wearing an attack-proof suit, plays an armed con taking on German shepherd Merlin.

There is only one winner as Merlin’s jaws lock around his arm.

Some recruits visibly shuddered as the instructor was hauled across the floor by the dog.

Recruits are warned never to rush to the aid of a handler injured in a riot.

If they did, they would face almost certain attack from the dog, trained to protect its handler at all costs.

We also saw the NTRG teaching the Tornado teams how to deal with rioters at close quarters, breaking down barricades while under attack.

Just as we were not allowed to show the faces under the riot helmets, revealing precise details of the unit’s tactics was also off-limits.

Even some of the more secretive parts of their kit have had to be blurred out in our pictures for security reasons.

As NTRG director Stu Hardy, 53, told us: “We have kept a very low profile as a unit for a reason.

“Even though we are talking about it now, there’s still part of me that would prefer us to remain in the shadows.”

The task faced by the NTRG is as tough as it gets.

Last year it was called out more than 400 times to incidents including riots, hostage situations and rooftop protests.

Founded in the early Eighties, the NTRG has grown from 12 officers in 2000 to 41 today.

Despite a £1.5million annual budget, its ranks remain small — perhaps unsurprisingly so.

The unit operates 24 hours a day, 365 days a year and is seen as the “elite of the elite” within the Prison Service.

Hopefuls first have to pass an advanced “bleep test” to prove their fitness before being asked to hold a heavy riot shield at an uncomfortable angle for a minute.

Then the really hard work begins.

Stu, who is deceptively softly spoken, said: “It takes two years for a new recruit to be up to what I’d call general standard.

“But to get to a specialist level in tactics like methods of entry and working at height would take another five years. So you’re talking seven years’ training.

“I want team workers. I don’t want individuals. I want people who’ll complement each other in the toughest situations.”

Stu added: “It’s not for everyone.”

For many prison officers, the NTRG is the pinnacle of their industry.

There are 30 applicants for every post and dozens apply every time a vacancy arises.

Last night, Mr Gyimah paid tribute to the unit.

He told The Sun: “The elite nature of the NTRG is just one example of the talent and training the Service has at its disposal.”