Britain’s Special Forces will be charged with a new mission tracking the threat posed by “hostile” state actors around the world, the head of the Army has said.

In an interview with The Sunday Telegraph, General Sir Mark Carleton-Smith suggested the SAS and SBS would be put on a “different trajectory” in a major overhaul of the armed forces to be announced on Monday.

The paper said that it could mean Special Forces soldiers operating alongside MI6 to mount surveillance operations against Russian intelligence and military units.

Gen Carleton-Smith said some of their traditional roles would now be taken over by a new Ranger Regiment announced on Friday ahead of the publication of the Defence Command Paper.

He said that in future Special Forces “will be tracking the changing and accelerating nature of the threat.

“The most persistent and lethal threats are those associated with hostile state actors.

“So they’re tracking a different trajectory and what they leave behind is a vacuum where they need to hand off tasks, missions and responsibilities to a second echelon force.

“The Rangers will fit neatly into that.”

The Telegraph said it was likely that Special Forces units would be tasked alongside MI6 with uncovering the activities of Russian military intelligence – the GRU – thought to be responsible for the Salisbury nerve agent attack on former spy Sergei Skripal and his daughter.

Defence Secretary Ben Wallace talking to troops
Defence Secretary Ben Wallace said UK enemies have ‘infinitely more options’ (Andrew Matthews/PA)

It said that elite units could also be charged with countering the activities of the Wagner Group, a Russian mercenary organisation widely thought to act as proxies for the Kremlin.

Writing in the paper, Defence Secretary Ben Wallace said armed forces needed to adapt to counter threats which had “changed beyond recognition” in the past 30 years.

“We can no longer take for granted the superiority of Western capabilities. Our enemies have infinitely more options,” he said.

“Encryption, precision, and information operations complicate the threat picture. We find ourselves constantly confronted in the ‘grey zone’ – aggressive actions below the threshold of open conflict.”

He said there would be additional investment for “intelligence, surveillance and reconnaissance” as well as for electronic warfare.

The National Cyber Force will be expanded, there will be a new Space Command to co-ordinate military and commercial operation and the Royal Navy will get a new Multi Role Ocean Surveillance ship (MROSS) protect vital undersea cables.

While the paper said the Army would get an additional £3 billion, there would also be cuts with a reduction of around 10,000 troops expected  as well as cuts to armoured fighting vehicles and the last remaining C-130J Hercules transport aircraft.