Britain is leaving itself open to allegations it is complicit in torture by sending failed Tamil asylum seekers back to Sri Lanka despite evidence physical abuse is a "daily reality", a charity warns.

UK 'complicit in torture' as Tamils return to Sri Lanka. (Getty)

The charity Freedom from Torture said a number of Tamils were due to be forcibly removed by the UK Border Agency and flown back to Sri Lanka on Wednesday.

The group says it has credible evidence that members of the Tamil minority are still being routinely mistreated following the end of the country's bloody civil war.

Speaking at an event at the Labour Party conference in Liverpool, the charity's chief executive Keith Best called the present government's position "untenable".

The meeting, hosted by Channel 4 News Foreign Affairs Correspondent Jonathan Miller, featured mobile phone footage from the documentary Sri Lanka's Killing Fields, which showed presumed members of the Tamil Tigers guerrilla group apparently being executed by soldiers of the Sri Lankan government.

'Faked footage'

The country's rulers strongly deny allegations of war crimes and says the footage was faked.

The Sri Lankan government's Lessons Learnt and Reconciliation Commission is due to publish its own report into the civil war in November. The human rights charity Amnesty International has called the internal investigation "flawed at every level".

Torture is continuing to take place after the conflict has ended. Torture is now a daily reality in Sri Lanka. Keith Best

A United Nations panel of experts has concluded that there is "credible" evidence of war crimes and crimes against humanity by both sides.

Mr Best said the defeat of the Tamil Tigers in 2009 following decades of civil war in the Indian Ocean island nation in 2009 did not mark the end of atrocities carried out by government agencies.

'Torture is continuing'

Two years after the bloody end of the conflict, which saw tens of thousands of civilians lose their lives, thousands of displaced people - many accused of being former Tamil fighters - are still being held in camps.

Mr Best said there was evidence of forced labour, beatings and sexual abuse in some of the camps.

He said: "Torture is continuing to take place after the conflict has ended. Torture is now a daily reality in Sri Lanka.

"There is sufficient evidence that people being sent back will face torture. It is an extremely disturbing move.

We have seen evidence of the fact that these people in these camps are being regularly abused, both males and females being raped and subjected to some other forms of torture."

The charity played a recording of an alleged torture victim who said he was tortured with "burning irons" by Sri Lankan government forces, because his brother had been forcibly recruited by the Tamil Tigers. He was only freed when his family paid his torturers a ransom.

Mr Best added that the British government may be laying itself open to allegations that it is complicit in human rights abuse if it returns people to a country where they are likely to be tortured, and fail to monitor what happens to them.

He said Amnesty had collected evidence of people who were flown back to Sri Lanka by the Australian government being met at the airport by Sri Lankan police and tortured.

Mr Best said: "There is no evidence that the (British) government is attempting to monitor what happens to those people who go back.

"Will we know what happens to those people who go back on Wednesday, assuming that flight takes place? No.

"The position of the present government is untenable. To say that we need to wait for the Lessons Learnt and Reconciliation Commission is an appalling abnegation of any kind of responsibility.

"Should we be returning people to Sri Lanka. Should we be a country that has a degree of complicity? Is it not far too dangerous for the Government to leave itself open to the allegation that it is complicit in what happens to those people on their return?"

Shadow Foreign and Commonwealth Office Minister Emma Reynolds said she had visited Sri Lanka and been allowed to speak directly to inmates at a camp for displaced people.

She said: "They have been held now for a couple of years and they haven't had due process. Many of them are not fighters, but worked as administrators in the area run by the LTTE."