Storm Shadow is a British, French and Italian air-launched cruise missile, manufactured by MBDA. In French service it is called SCALP EG. Storm Shadow provides long-range air to surface capabilities and it is one of the most advanced missiles of its kind. Credit: Handout.

For ten straight days, UK Typhoon FGR4 fighter bombers unleashed deadly Storm Shadow bunker buster bombs on IS cave hideouts.

Again and again and again.

Storm Shadow is an air-launched, stealth, cruise missile costing £790,000.

It flies at a subsonic 800 mph and can travel 300 miles, earning its name of a “stand-off” weapon.

It is one of the UK’s “bunker-busters” and is aimed at penetrating through rock or concrete, attacking airbases, radar installations and big port facilities.

In other words, no prisoners.

And for this reason, it is widely believed, that this classified operation in northern Iraq — revealed only now — killed dozens of IS ­terrorists.

Explosives and weapons caches and a bomb-making hub were also reportedly destroyed.

According to reports in the UK’s Mirror, the operation signals a ­stepping up in the UK and American military’s determination to try to wipe out IS’s ability to resurge in the war-battered region.

The RAF operation was launched against the terror group in the Makhmur mountain region of northern Iraq, south west of the Kurdish capital city of Erbil.

Until now the operation – which was launched in late March and concluded earlier this month – could not be revealed, the Mirror reported.

The assault followed weeks of ground offensives launched by British-trained Iraqi special forces, which drove the militant fighters into their heavily protected underground tunnels.

Once they had been observed by drones, RAF commanders, along with American and French military, decided to launch the offensive, the Mirror reported.

The “deep strike” Storm Shadow onslaught was aimed at holding back an IS uprising in the region prompted by ex-US President Donald Trump’s ­threatened troop withdrawal.

Analysts say it marks a turning-point in the ­coalition’s long-term operations against IS, signalling a fresh determination by the Biden administration to once and for all wipe out the terror threat.

A UK defence source told the Daily Mirror: “There has been a significant increase in ISIS activity in the region in recent months and this latest operation has set them back a great deal.

A twin-engine AF Eurofighter Typhoon armed with a Storm Shadow missile. Credit: Handout.

“Many of the ISIS middle-ranking personnel seemed to be becoming bolder and had begun to move around both in Iraq and Syria, gaining confidence in attacks.

“The continued operation shows that we are able severely to limit their ability to manoeuvre and transport weapons and explosives around the region.”

Meanwhile, British defence officials ­reaffirmed their determination to campaign against the threatened IS comeback across Syria and ­neighbouring Iraq, the Mirror reported.

Defence Secretary Ben Wallace said: “The British armed forces, alongside our Iraqi and coalition ­partners, continue to root out Daesh terrorists from where they hide.

“The UK is committed to defeating Daesh. This operation will prevent the terrorist group and its toxic ideology from regaining a foothold in Iraq and reduce its capability to coordinate attacks around the world.”

Ministry of Defence sources revealed Paveway IV bombs were launched at IS targets, dealing a further blow to the group, the Mirror reported.

It is believed there are still as many as 10,000 hardline and heavily armed IS fighters across Iraq and Syria who are in close contact with thousands more “sleeper cells.”

The IS leadership has been able to keep hold of an estimated £350 million war chest to help recruit more young fighters and buy weapons to back their cause.

The bounty has been collected over seven years of bank robberies, ­extortion, outright theft and the illegal sales of oil stolen from Iraqi and Syrian wells, that much we know.

Coalition forces backed by Western troops completed the military defeat of IS in the region in early 2019, driving them out of Raqqa in Syria and Mosul in Iraq, the Mirror reported.

But the long-term coalition strikes, codenamed Operation Shader, and launched by UK warplanes from RAF Akrotiri in Cyprus, are being stepped up.

Storm Shadow is an Anglo-French low-observable air-launched cruise missile, developed since 1994 by Matra and British Aerospace, and now manufactured by MBDA. Storm Shadow is the British name — in French service it is called SCALP EG. Credit: Handout.

The RAF also hit targets in northern Syria, killing a group of IS fighters holed up 50 miles west of al-Hasakah, which is in the Kurdish-controlled statelet of Rojava.

These latest missions confirm that, although the pace of UK offensive air operations in the Middle East has diminished, the RAF is still very much on call and active when required, The Drive reported.

It is also telling that, by employing the Storm Shadow, the Typhoon has now well and truly assumed the mantle from the swing-wing Tornado GR4.

To allow the withdrawal of the Tornado, the UK first had to ensure that the Typhoon was able to employ the key air-to-ground weapons that had been used by the Tornado, under a program codenamed Centurion.

As well as the Storm Shadow — which was first used by the Tornado during the opening phases of the invasion of Iraq in 2003 and then subsequently during the air campaign over Libya in 2011 — the Typhoon was cleared to use the Brimstone precision anti-armor missile.

The warhead uses a precursor charge to punch through hardened structures followed by the main change that can be fuzed for penetration mode when required, meaning it detonates after breaching the target, The Drive reported.

The missile guidance system combines an inertial navigation system, GPS, and terrain referencing.

For a target like the Erbil caves there are currently no heavier (1,000- or 2,000-pound) Paveway guided bombs available to the Typhoon, and no other bunker-busting alternatives.

The Brimstone, for its part, offers a low-collateral, high-precision strike capability.

Air Commodore Simon Strasdin, Air Officer Commander of 83 ­Expeditionary Air Group and the UK Air Component Commander in the Middle East, said: “The Royal Air Force and wider coalition have supported an operation led by a highly capable unit from the Iraqi-Security Forces.

“Together, we’re working towards defeating the remnants of Daesh and ensuring its will is depleted. The commitment and ­dedication from the personnel deployed on ­operations across the Middle East is simply outstanding.

“It is even more impressive that the Royal Air Force can adapt and continue to deliver air power against the enemy during a global pandemic.”

Indeed, they can. But whether they can actually stamp out Daesh, is another question altogether.

Like Afghanistan, this could be yet another, war without end.