The man is young, naked, bound and blindfolded; a corpse lying across his legs. A soldier approaches him in what appears to be Sri Lankan army uniform and shoots him at point-blank range, apparently amused at the death. “It’s like he jumped,” he says.

The footage, released last night, appears to show what the Tamil community and human rights campaigners have long alleged: that in its final surge against the Tamil Tiger rebels this year, the Sri Lankan Army summarily killed prisoners.

Channel 4, which broadcast the video, says that it was recorded by a Sri Lankan soldier on his mobile phone in January, when government forces overwhelmed the stronghold of the Liberation Tigers of Tamil Eelam (LTTE) at Kilinochchi.

After the murder the video, taken in daylight, pans out to show eight bound corpses, all shot in the head and all but one naked. Voices in the background speak Sinhalese; as the footage concludes, viewers see a ninth bound victim shot.

The capture of Kilinochchi was a milestone in the army’s final push against the Tamil Tigers, which triumphantly concluded a 27-year war in May. But by January, when the video was allegedly filmed, foreign and most local journalists had been banned from the conflict zone.

NGOs and overseas observers were also largely kept away, meaning that the timing and location of the video are virtually impossible to verify. Channel 4 said that the video was smuggled out of Sri Lanka in the past two days by a group called Journalists for Democracy in Sri Lanka, which has previously issued statements through the Asian Human Rights Commission. Within moments of the video being posted online, Sri Lankans reported that they were unable to access the Channel 4 website.

The Tamil Tigers fought for nearly three decades for a separate homeland in Sri Lanka, using suicide bombers, child recruits and soldiers trained to swallow cyanide rather than be caught.

As the end of the war approached, the Government was accused of almost equally brutal tactics including, according to the United Nations and documents leaked to The Times in May, a share in the deaths of up to 20,000 civilians under mortar fire. It and the Tigers have used the news blackout surrounding the war to claim that accusations against them are fabricated.

The Sri Lankan High Commission in London said it categorically denied “that the Sri Lankan armed forces engaged in atrocities against the Sri Lankan Tamil community. They were only engaged in a military offensive against the LTTE.

“The High Commission has noted that in many instances in the past, various media institutions used doctored videos, photographs and documents to defame the Sri Lankan Government and armed forces. Therefore, we request you to verify the authenticity of the video footage.”

Reports in May said that government soldiers killed two high-profile Tigers, Balasingham Nadesan, the head of the LTTE political wing, and Seevaratnam Pulidevan, who led its peace secretariat, as they approached bearing a white flag and having asked by text message to surrender. The body of the Tigers’ leader, Velupillai Prabhakaran, was shown on government video having been shot in the head.

The Government, described by Amnesty International as “trapping the country in a vicious cycle of abuse and impunity”, has also been held responsible for murders beyond the battlefield such as the killing of Lasantha Wickrematunge, an anti-government journalist shot dead in Colombo in January.

In a posthumously published editorial, Wickrematunge said that the Sri Lankan President and Government would be responsible for his death.

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