'Col. Karuna', a renegade Tamil Tiger leader who rights groups say committed war crimes in Sri Lanka, has been released from a British jail ahead of possible deportation to his country.

Karuna Amman, whose real name is Vinayagamoorthi Muralitharan, was transferred to an immigration detention centre Thursday because of insufficient evidence to convict him for war crimes, the British home ministry said Friday.

Karuna was arrested in November 2007 and jailed in January for entering Britain under a Sri Lankan diplomatic passport issued under a false name.

Sri Lankan diplomats said he was likely to be deported.

'We have not yet received a request for the temporary travel documents that are needed to deport a person but we expect that to come,' a diplomat told IANS.

The Crown Prosecution Service - responsible for taking police cases to court in England and Wales - said there was 'insufficient evidence to provide a realistic prospect of conviction for any offences in the case of... Col Karuna.'

Karuna's lawyer, David Phillips, says he has not claimed asylum so far and although he could apply from the detention centre, his chances would not be very high because he failed to declare his intention to seek asylum immediately upon arrival in Britain.

During his court case, Karuna said he had received the false diplomatic passport from the Sri Lankan government.

He said that Sri Lankan Defence Secretary in Colombo Gothabaya Rajapaksa, the brother of President Mahinda Rajapaksa, had arranged the documents for him.

The Sri Lankan government denies it has any links to Karuna.

A former area commander of the Liberation Tigers of Tamil Eelam (LTTE), Karuna broke away from the group in 2004.

Human rights activists allege he then joined hands with Sri Lankan authorities. They say he participated in death squad activities against civilians and forcibly recruited children into his Karuna faction.