HIGH above the Baltic Sea, pilot Flight Lieutenant Andy Roberts runs through a range of unlikely sounding scenarios ahead of landing the RAF’s £152m air-to-air refuelling Voyager aircraft at Siauliai air base for the first time.

Flt Lt Roberts concludes by informing his two co-pilots there is enough fuel on board to return to RAF Brize Norton, and if a landing there is impossible, to fly on to East Midlands Airport, with an extra 90 minutes of fuel for thinking time.

Minutes later, the difficulties of rapidly establishing an RAF base in a foreign country with a language barrier rapidly become apparent, as does the need for exhaustive planning.

As the Voyager, the RAF’s largest ever aircraft, approaches Siauliai and a torrential storm breaks, the Lithuanians turn off their radar and landing systems, forcing the Voyager to circle to regroup before going in to land.

At just 50ft above the ground, the Voyager pilots spot the Lithuanians have left a cable stretched across the runway to stop fighter jets with hydraulic failure.

In an instant, the 240-tonne plane swoops skywards, averting a probable disaster.

Twenty minutes later the Voyager has landed at the former Soviet base, and the crew are met by relieved colleagues who began establishing a British base there, 55 miles from the Russian enclave Kaliningrad, last month.

Over the past ten years the NATO-led Baltic Air Policing Mission has seen its members deploying fighter aircraft to secure airspace over Estonia, Latvia and Lithuania, which do not have their own fighter aircraft, to provide reassurance to the NATO allies.

In response to Russia’s role in the Ukraine crisis and mounting international tensions, Britain dispatched 135 Expeditionary Air Wing Headquarters, based at RAF Leeming, near Bedale, North Yorkshire, and four Typhoons to Lithuania to support Polish fighter jets.

Defence Secretary Philip Hammond has warned Russian president Vladimir Putin not to breach a red line around the Baltic States, saying it was clear Moscow “does not accept the norms of international behaviour”.

The RAF jets will be on standby 24 hours a day to police the skies above Lithuania for the next four months.

Wing commander Dylan Eklund, whose family live near Northallerton, said: “Should anything approach the Lithuanian air space that can’t be identified by other means, Typhoons or Polish MiG-29 fighters will approach the aircraft.

“For the RAF this is very much core business, but because it is a different location there are different aspects to it and a different atmosphere.”

Some personnel at Siauliai said they were following the Ukraine crisis closely and their mission in Lithuania had a Cold War feel to it, and contrasted it to that in Afghanistan, as they were “dealing with Russia, rather than guys with home-made bombs and AK47s”.

But for RAF Leeming’s 90 Signals Unit Squadron Leader Ian Tanfield, a married father-of-three from Redcar who is in the last ten months of a 37-year career with the force, the mission is not obscured by international politics.

He said: “We are here to ensure the Typhoons can operate safely, we have a lot of danger areas to look out for.

“When we arrived three weeks ago it was just an open pan of concrete, and progress has been rapid with great support from the locals, and our small team working exceptionally hard.”

It is understood RAF personnel have worked up to 15 hours a day establishing the base after being given a week’s notice of deployment.

The principle of setting up mobile RAF bases began during the Second World War, to support tanks on the rapidly moving frontlines in north Africa and Normandy.

On his first operation, Flight Officer Benjamin Ireland, 23, of Marske, said it had been exhilarating being involved in building a base in three weeks, but remained aware of his parents’ apprehension ahead of him being deployed.

The armaments officer said: “It has proved to me how accurate our training exercises are. This is much more exciting than being at home.”

The 100-strong RAF team at Siauliai features experts in fields ranging from weather forecasting to medicine.

Communications expert Corporal Stewart Pierson, of Sedgefield, arrived at the base first, establishing secure satellite contacts to Britain, while his colleague Senior Aircraftsman Dex Unwin has set up miles of cables from the control tower to alert the Typhoon pilots’ to emergency situations.

Cpl Pierson, who will celebrate his 36th birthday next week, said he remained unclear as to how long his deployment would last.

He said: “My son is never happy that I go away, but it is good to have a son who is proud of what I do.”

At the heart of the Siauliai operation are the Typhoon aircraft, which are in the air about five minutes after the alarm is raised.

The pilots sprint across the tarmac, start the ignition systems, taxi on to the runway, and with a deafening whoosh take to the skies to identify rogue aircraft.

Ahead of the 400mph Voyager arriving in Lithuania, the Typhoons serenely intercepted the giant aircraft, as part of training for how it might respond if a Russian snooper plane came into Lithuanian airspace.

Typhoon pilot Flight Lieutenant James Skinner, whose training involved a stint at RAF Linton-on-Ouse, near York, said: “Scrambling a Typhoon gets your heart going and makes you think very quickly – you have to rely on your training as you never know what you are going to.”