These guards in the Borjomi region of Georgia - trained by US army and SAS veterans - are pawns in a new great game gripping Central Asia: their job is to protect the oil pipeline buried 10ft below.

"A terrorist attack is the greatest threat we face," says the guards' commanding officer, Lieutenant-Colonel Giorgi Pantskhava, an energetic Georgian in desert fatigues and aviator shades.

The $4bn (?2.2bn) BTC - Baku Tbilisi Ceyhan - pipeline comes on stream today It is key in American plans to reduce dependency on Opec oil producers in the turbulent Middle East. Pumping oil 1,000 miles from the Caspian sea to the Mediterranean through Azerbaijan, Georgia and Turkey, it will avoid Russia - increasingly seen by the US as a resurgent superpower prepared to use control of energy resources as a political weapon.
The pipeline - 70 per cent funded by the World Bank, the European Bank for Reconstruction and Development, and export credit agencies - took three years to build and will carry up to one million barrels of oil a day to western markets. Yet its position on the faultline between Russia and its estranged former Soviet neighbours makes it a shaky bet.

The fiercely pro-Washington government of Georgia's president, Mikhail Saakashvili, welcomed the BTC with open arms, saying transit payments would help to kick-start the economy of the faltering ex-Soviet state.

Since coming to power in 2004 Saakashvili has steered his country away from Russia towards co-operation with the US. 'Georgia will be America's partner in spreading democracy around the world,' Bush told rapturous crowds during the first visit of a US president to the country last year. Yet the pipeline, constructed and run by a BP-led consortium, will open in the teeth of bitter opposition.

Green campaigners say the route passes too close to Georgia's Borjomi Gorge, a tourist spot with mineral water springs and abundant wildlife. 'If there is even a minor oil leak here then the reputation of the area will be irreparably damaged,' says Vano Shalutashvili, of the Borjomi People's Democracy Institute, a non-governmental organisation that has fought for the pipeline to be diverted. A leak on one section was detected in a test run this month.

Critics also say BTC passes too close to volatile breakaway regions in both Georgia and Azerbaijan, making it vulnerable to sabotage that could cause a catastrophic spill.

Georgia's interior ministry is taking no chances. Original plans to patrol the BTC route with unmanned reconnaissance aircraft were dropped in favour of small, roving anti-terrorist squads. Yet even these might not be able to prevent an attack, as another guard admitted: 'Iran may try to strike it with a missile and we shouldn't forget that Russia is the primary expert for techniques in blowing up pipelines,' he said.

Locals are furious with BP, claiming a host of negative consequences from the construction: houses damaged by heavy traffic, low compensation for lost land, and polluted springs. Pavel Poshnakhov, 45, a villager in Tsikhisjvari, said he had to show his passport to guards when he crossed the corridor with his cattle, or went to collect firewood.

/observer.guardian.co.uk/