Victims will tell how the programme helped to catch the criminals, and detectives will talk about their work with the 37-year-old anchorwoman.

The show will also open without its normal titles and music, and will begin with a reconstruction of Ms Dando's murder last month.

Police are still hunting the killer

However, BBC bosses said that beyond that, the edition will stick to the usual Crimewatch format, with appeals for help over three other crimes.

A corporation spokesman said: "Many high-profile tributes have been rightly paid to Jill but she believed passionately in the public service performed by Crimewatch and she greatly valued her work on it.

"It seemed right, therefore, that ordinary people who have been helped by Crimewatch and who contacted us to say that they would like to make a tribute to her should be able to do so."

Nick Ross has revealed that filming the edition of the programme has helped him deal with her death.

He said the show, the first since Ms Dando was killed on the doorstep of her west London home with a single pistol shot to the head, would be the most difficult any of the production crew had taken part in.

'Most difficult programme'

But by working on the reconstruction, everyone felt they were helping detectives with the murder hunt.

"It seems quite unreal doing an appeal about Jill rather than with her," Mr Ross said.

"The whole team had been so upset by her death, and yet at least all the work on the reconstruction and other planning makes us feel we are doing something useful, a privilege most friends and relations of victims don't have.

"We all know it will be the most difficult programme any of us will ever be asked to do."

Programme editors will decide hours before the show which scenes of the murder reconstruction to include, after spending two days filming in the Fulham street where the presenter lived and was murdered.

The reconstruction will be accompanied by a live interview with the man leading the Scotland Yard murder hunt, Detective Chief Inspector Hamish Campbell.

South Africa connection

Detectives are still baffled as to a motive for the murder, after almost three weeks of investigation.

On Monday, South Africa's police service confirmed that it has joined the hunt for her killer at the request of UK police.

They obtained a statement from the parents of a South African citizen, who is presently residing in London, confirming that his personal firearm was still in South Africa.

A police spokesman said the parents had confirmed that the gun was with them. The South African citizen was, as far as he knew, not a suspect in the case.

Much has been made in the press of Ms Dando's brief liaison with a South African game ranger whom she met in 1996 while filming in the country.