He was held in custody overnight at a central London police station after being arrested at his London home on Thursday, said a Scotland Yard spokeswoman.

Yard sources said the man was not a strong suspect and was thought to have been visited by officers following a telephone tip-off.

He was not believed to be the prime suspect identified in an E-fit as the man spotted sprinting away from the scene of the murder in Fulham, west London, on 26 April.

E-fit suspect

This was the first arrest to have been made by detectives investigating the BBC TV presenter's death.

The E-fit was compiled from the evidence of a witness in the Fulham Palace Road who saw a man sweating heavily at a bus stop minutes after Ms Dando was shot on her doorstep.

Detectives believe that a figure from the 37-year-old Crimewatch host's past or a stalker is most likely to be behind the killing.

Yard sources said names were often thrown up during high-profile murder cases, and they always had to be followed up.

Bungled escape?

Despite numerous sightings of a man fleeing from the scene, detectives remain puzzled about who the man was and what his motive might have been.

It is thought that he could have been working as part of a hit team, and was possibly planning to escape in a blue Range Rover that failed to pick him up.

A speeding Range Rover was sighted heading towards nearby Putney Bridge and the prime suspect himself boarded a number 74 bus before getting off at Putney Bridge tube station.

In accordance with new regulations introduced since the inquiry into the bungled Stephen Lawrence murder hunt, a team of senior detectives has been reviewing the case.

The team was brought in earlier this week, after 28 days had passed since Ms Dando's murder.