A Ukrainian soldier fires a shoulder-mounted Starstreak missile

Brimstones can be used against tanks, artillery and some smaller vessels such as landing craft, according to Capt Chris Carlson, formerly of the US Navy.

The missiles are normally fired from aircraft, but in Ukraine they are being modified to be fired from trucks.

Launching them from the ground reduces their effective range, says Capt Carlson.

If used as anti-ship missiles, Brimstones are far too small to sink larger vessels, but could cause substantial damage.

“It all depends where you hit,” he says. “If you went through an engine or near the water line, you could give an enemy some serious trouble.”

Britain has donated 120 armoured vehicles to Ukraine, including Mastiff patrol vehicles.

Mastiffs were very popular among British troops in Afghanistan as they provide a high level of protection against landmines and improvised explosive devices.

Analysts say that in an area which as been as heavily mined as the Donbas, Mastiffs are likely to be very useful.

It is understood that both sides in the conflict have used landmines extensively, often to force enemy vehicles into areas where they can be targeted with anti-tank weaponry.

The Ministry of Defence says it is supplying “dozens” of heavy lift unmanned aerial vehicle (UAV) systems to provide logistical support to isolated forces.

Analysts say that drones can be very effective in getting supplies over the “last mile” to front line troops, particularly under threat of Russian artillery fire and in situations where there is a risk of encirclement.

While Russia has so far failed to encircle large numbers of Ukrainian troops in eastern Ukraine, the threat of artillery fire in some areas is ever-present.

“It’s the sheer quantity of stuff needed by troops,” says Mr Bronk. “Every time you can use a drone instead of a soldier to get supplies forward is one less time someone is exposed to extreme danger.”

Britain says it has donated five air defence systems, including Starstreak missiles.

Starstreak is designed to bring down low-flying aircraft at short range.

It ignores counter-measures such as flares and chaff deployed by many aircraft.

“From a pilot’s point of view, Starstreak is a very unpleasant thing,” says Mr Bronk. “There’s very little you can do about it.”

He says Russian forces may deem some operations too risky if they are aware that a weapon as deadly as Starstreak is on the ground.

However, Starstreak requires much more training than systems such as Nlaw, and is no substitute, say analysts, for longer-range air defence systems.

Britain is also supplying a “small number” of tracked Stormer vehicles to act as a mobile platform for Starstreak missiles.