The RAF’s senior intelligence and surveillance officer launched a passionate defense of the Sentinel program yesterday, as the perennially overworked yet permanently under-threat system faces yet another period of uncertainty about its future.

Air Commodore Dean Andrew, commander of the RAF’s ISTAR (intelligence, surveillance, target acquisition and reconnaissance) force, intends to fight the decision – announced in last year’s Strategic Defense and Security Review (SDSR) – to remove one of the five Sentinel aircraft from service in September. His efforts are being supported by Raytheon, the prime contractor on the program, which fields a SAR/GMTI (synthetic aperture radar/ground moving target indicator) sensor onto a modified Bombardier Global Express jet that has seen heavy use since its entry into service in 2007.

“I can’t overturn [the SDSR decision],” he said, “but I know some people that can, and I’m going to lobby them. We need five aeroplanes in the fleet to provide the capability. If we don’t have five in the fleet, then the ability to provide that capability as regularly as we do will reduce. It makes no sense to me to do that.”

Andrew compared the SDSR decision ­– which also committed to remove Sentinel from service in the 2020s – to another taken recently in Britain.

“Imagine we’d just voted to leave the European Union, yet there were people out there going, ‘That was a really silly idea – we’d like to reconsider’,” he said. “It’s in the same space. Maybe [the SDSR decision] was a good idea at the time. But I’m the operator, and it’s bad enough when I’ve got five. The people that want this capability aren’t going to [care] about that I’ve only got four – they’ll still want them there. The easiest way this enterprise can continue to provide this capability to save people’s lives is to have five.”

The lack of a jet at the Airshow has not helped Sentinel’s cause. But with the tiny fleet in such huge demand – two jets are deployed on Op Shader in the Middle East, one is in maintenance and the others required for training – the ISTAR force does not have one to spare for PR work. The complicated, often classified, difficult-to-explain nature of the ISTAR fleet’s job makes mounting a case to the public – and their representatives – a challenge.

“Every single capability we [in the ISTAR Force] have is essential to saving lives,” Andrew, a former Tornado operator, said. “But because it doesn’t hover it doesn’t grab the attention. I’ve dropped bombs all over the place, but only now do I realize who told me where to go. I spend all of my time standing up, talking outward and upward, to try and express to people how important this capability is.”

Focus has also been turned away from Sentinel by news of the UK’s confirmed order for nine Boeing P-8s. The new anti-submarine aircraft will begin to be available around the time Sentinel is presently scheduled to leave service, but according to Andrew, whose responsibility includes P-8, any thoughts that the new fleet can absorb Sentinel’s mission seem overly optimistic.

“Nine is not enough,” he said. “If you look at the modus operandi of how we’ve done this before, nine is only enough to do over the sea.”

The frustrating irony is that Sentinel’s value has not been in doubt since shortly after the Conservative-Liberal Democrat government announced its cancellation in the 2010 SDSR. During Operation Ellamy, the UK’s contribution to the NATO campaign over Libya, Sentinel was unique across the coalition in its ability to map the ever-moving front line through GMTI coverage of milling ground vehicles. Deployments to Mali, Nigeria and even mapping flooding in southern England followed. The then prime minister, David Cameron, announced a reprieve to the cancellation at Farnborough in 2014: he is known personally to have requested Sentinel product during briefings.

“This is still the Prime Minister’s go-to airplane,” Andrew says. “It’s a matter of time before people go, ‘I am not going to accept a gap in capability.’ It’s about a stovepiped understanding here, a stovepiped understanding there. As the warfighter, we understand the whole enterprise. What I can’t afford to have happen is to take an aeroplane out of service, close the base, then six years later put it in the base down the road. Because if I do that I’ll lose all that experience. I think it’s unimaginable we would do that [with Sentinel].”