The Sun, which firstly broke the narration, said ratings had suffered as it was scheduled against Cold Feet and Broadchurch .

Three bouts have aired this year – in February and March – watched by an average of virtually three million viewers. That is down from 14 million who watched at its peak.

Nick Ross on Crimewatch’s ‘huge impact’

Speaking on BBC Radio 4’s Today programme, onetime Crimewatch presenter Nick Ross said: “I’m astounded that it’s has been going on for so long. And it’s a tribute to the team they’ve restrained it croaking.

“When it started, it was progressive. Up to that point, television and radio basically talked at the audience. There was no internet, very little phone-ins, this was a programme where the gathering could talk back and could actually influence the end of the programme.

“This sort of progressive happen then had a huge impact on television generally and has retained going for 33 years despite all the changes in technology.”

Ross said descending ratings had had an impact on crime-solving.

“If you get 15 million people watching a programme and you have an appeal, opportunities of concluding person, that one witness who saw something they had no impression was connected with the crime … they are unable ring in.

“Once your gathering starts slumping, you go back to two million, one million, your chances of meeting that person are so remote.”

Other previous Crimewatch presenters include Jill Dando, who was murdered in 1999 – with her own lawsuit being boasted on the reveal.

Dando, one of the BBC’s best-known Tv identities at the time, was shot dead on her doorstep in west London.

Barry George was imprisoned of her carnage in 2001 but was acquitted of the killed at a new trial in 2008 after fear was thrown on the reliability of gunshot residue manifestation. Her gunman has all along been found.

Other Crimewatch emcees over the years include Sue Cook, Kirsty Young, Fiona Bruce and Rav Wilding.

The big cases Crimewatch cured solve