A group of 50 Sri Lankans are heading home on a special chartered flight arranged by the UK Border Agency (UKBA), they said.
The deportation takes place despite a protest from the London-based rights group Human Rights Watch (HRW) which accused the UKBA of turning a blind eye to the conditions faced by the returnees.
"In its haste to be tough on failed asylum seekers, the British government is turning a blind eye to compelling evidence that Tamils deported to Sri Lanka risk torture on arrival," a HRW release said.
A large majority of failed asylum seekers are from the Tamil minority community who fled the island at the height of the civil war between 2006-09.
