Britain is facing fresh allegations of complicity in the killings of terrorism suspects by Kenyan death squads.

The claims come from members of Kenyan intelligence and special police units who say they carry out extrajudicial killings. They also say they have received training and intelligence from Britain’s military and other officials as part of their counter-terrorism efforts.

The members of these death squads say they have not turned whistleblowers because they believe the killings are wrong, but because they believe Kenya has little choice in the face of vicious Islamist insurgency.

The claims come in an al-Jazeera investigation programme to be broadcast on Monday.

One of those interviewed claimed Britain knew of the killings the Kenyan death squads carried out: “Once they give us the information, they know what they have told us it is ABCD: ‘Mr Jack’ is involved in ‘such and such’ a kind of activity. Tomorrow he’s no longer there. We have worked. Definitely the report that you gave us has been ‘worked on’.”

A Kenyan intelligence officer claimed Britain knows of the elimination programme: “Yes. When these people come for their training, I believe that all this information is being passed to them.”

Britain has faced previous allegations that its counter-terrorism efforts have led to complicity in human rights abuses overseas. Last week’s parliamentary report into Fusilier Lee Rigby’s death found Britain had a close relationship with Kenya’s anti-terrorism efforts, spearheaded by the anti-terrorist police unit, ATPU.

The intelligence and security committee report criticised the UK government and MI6 for not pressing Kenya hard enough about its human rights record as it fights terrorism, accepting Kenyan assurances at face value. It added that the ATPU “has a close working relationship with HM government”.

For many years Kenya has faced an Islamist terrorist threat and is currently battling al-Shabaab extremists based in neighbouring Somalia. Last year a Nairobi shopping centre, the Westgate, was taken over by terrorist gunmen who went on a killing spree leaving 67 people dead before Kenyan force ended their rampage.

• Inside Kenya’s Death Squads, al-Jazeera, airs on Monday 8 December 2014 at 8pm