Britain is “fully cooperating” with an investigation into the murder of a Kenyan woman whose body was found in a septic tank close to a UK army camp, a top diplomat has said.

High Commissioner to Kenya Jane Marriott said the UK will support the inquiry into the “tragic death” of Agnes Wanjiru in 2012 and “help in any way we can”.

The public commitment came amid growing calls for justice more than nine years after the killing of the 21-year-old and demands for a probe into any possible military cover-up.

The body Ms Wanjiru was discovered at the Lions Court Inn in Nanyuki two months after she disappeared in March 2012.

The town, which lies some 122 miles (196km) north of the Kenyan capital Nairobi, is close to the British Training Unit Kenya, which is commonly known as BATUK.

An initial inquiry stalled, but a fresh investigation was launched after an inquest delayed until 2019 found Ms Wanjiru was unlawfully killed, The Sunday Times reported last month.

The paper this weekend said a soldier accused of the murder had been named by fellow troops.

He allegedly confessed to the killing, and another soldier reported it to senior officers at the time, but no action was taken.

A post-mortem examination found Ms Wanjiru died as a result of stab wounds to her chest and abdomen.

There was also evidence she had been beaten, although due to the condition of her body it was unclear whether she had been sexually assaulted.

Witnesses told The Sunday Times that Ms Wanjiru, a sex worker, was last seen leaving the hotel’s bar with a British soldier.

Responding in the wake of the latest reports on Twitter, Ms Marriott said: “I share the concern about the tragic death of Agnes Wanjiru in 2012 – my thoughts are with her family and the community.

“I can assure Kenyans that the UK is fully cooperating with the investigation and will help in any way we can.”

A previous investigation into her death foundered when a request by Kenyan police in June 2012 to the British Royal Military Police (RMP) that nine soldiers be questioned apparently went missing.

The Sunday Times reports the man who allegedly admitted to the killing was not among the group.

Ms Marriot said: “In 2012, the UK’s Special Investigation Branch carried out initial enquiries in Kenya, including providing information about British personnel to Kenyan police. No further requests were received at that time.

“Following the conclusion of a Kenyan inquest in 2019, we understand that the Kenyan authorities are looking into the murder.

“We will support that Kenyan police investigation.”

She added: “The conduct of the UK military here is incredibly important to us.

“They do a lot of good in Nanyuki, for the economy and the community.

“But where there are issues, we have and will address them.”

In a statement on Twitter, BATUK commander Colonel Duncan Mann, said: “The British army is committed to upholding the highest standards of discipline, lawful behaviour and respect for others

“We are supporting the Ministry of Defence’s discussions with Kenyan authorities as they investigate the circumstances of Agnes Wanjiru’s tragic death.

“The jurisdiction for this investigation rests with the Kenyan Police.

“BATUK has and continues to play a positive role in the Nanyuki community.

“Due to this being subject to an ongoing investigation it would be inappropriate to comment further.”

Labour’s shadow defence secretary John Healey said: “The details of this young Kenyan woman’s death are dreadful, yet there’s still no action from defence ministers on reports of grave failings by the British military exposed in this case.

“Nine years on, justice must now be done for Agnes and her family.

“The defence secretary must take this more seriously.

“He should pledge the fullest co-operation to Kenyan detectives and launch an inquiry into any possible cover-up from commanding officers, military police or the MoD.”

A MOD spokesperson said: “The defence secretary is impatient with the pace of this and has directed full cooperation.

“He is working with the military and Kenyan police to ensure their investigation is not impeded.”