The BBC has said it is “extremely sorry for the distress” caused to the mother of a murdered schoolgirl who says Martin Bashir took her daughter’s clothes and never returned them.

Michelle Hadaway claims Bashir obtained the clothes for DNA testing for a programme for BBC Two’s Public Eye programme 30 years ago, but the investigation did not air and her calls to the broadcaster were ignored.

Ms Hadaway’s daughter Karen and her friend Nicola Fellows were found sexually assaulted and strangled in a woodland den in Brighton in October 1986 in what became known as the Babes in the Wood murders.

The families of the two girls spent decades fighting for justice after their killer, Russell Bishop, was initially found not guilty of their murders in 1987.

Ms Hadaway previously said Bashir came to her in 1991 and asked to have her daughter’s clothing DNA tested, saying that science had advanced in the five years since the murders, but never returned the clothes.

Following an investigation by the Mail on Sunday, the BBC said it was “appalled” that the clothing had been lost.

A BBC spokesman said: “The BBC is extremely sorry for the distress this has caused Ms Hadaway and we deeply regret we have not been able to give her any answers about what happened.

“We are appalled that this clothing was lost after being obtained as part of an investigation for a BBC programme.

“We are continuing to look into this matter following the Dyson inquiry, and as part of that, we asked a former senior BBC executive to review what happened in this case, including the 2004 investigation, and see if anything was missed which could help us locate the clothing.”

The BBC described claims that in 2004 the BBC investigations unit did not make contact with individuals who might have known where the clothing was as “incorrect”.

It added: “Records show that (Public Eye editor) Nigel Chapman and an individual who can be identified as (assistant producer) Charlie Beckett were contacted during the 2004 investigation.

“Martin Bashir was contacted via his agent, who told us that Martin was unable to assist with the whereabouts of the clothes.

“Eileen Fairweather had left the employment of Public Eye before the clothing went missing.”

The Metropolitan Police recently announced that a criminal investigation will not be launched into Bashir’s incendiary interview with Diana, Princess of Wales.

Lord Dyson’s blistering report criticised the methods used by Bashir to obtain his exclusive 1995 interview with the princess.

BBC director-general Tim Davie is due to appear before the Digital, Culture, Media and Sport Committee on Tuesday.