The Daily Mail says it is putting up the reward in the hope someone will come forward with a vital clue in the hunt for the man who murdered Ms Dando.

The Crimestoppers Trust announced on Thursday it was also offering a £50,000 reward. The money is believed to have been donated by an anonymous businessman.

The 37-year-old presenter of Crimewatch UK was shot in the head on the doorstep of her home in Fulham, west London, on 26 April.

The BBC's Stephen Cape: "An unknown business man has added another £50,000 to the reward"

The man in charge of the inquiry, Detective Chief Inspector Hamish Campbell, said of the Mail's offer: "This is an extremely large reward and shows the determination of the Daily Mail to assist the police and the public to identify whoever killed Jill Dando.

'This could be the trigger'

"I believe this sum of money might just trigger someone who knows the true story of what happened on that day to get in touch and tell us."

Later he held a news conference to dispel some of the "speculation" which had appeared in the media about Ms Dando's death.

The Daily Mail announced the reward on its front page on Thursday, and said it had taken the "unusual decision" after "lengthy consultation" with the family and senior Metropolitan Police officers involved in the case.

It said it had the full backing of the Dando family, and quoted Ms Dando's brother Nigel as saying: "I am very pleased about the Daily Mail's positive action and hope it will lead to the arrest and conviction of whoever is responsible for my sister's murder."

'No silencer used'

An E-fit of the suspect

Mr Campbell said he wanted to dispel several inaccuracies which had appeared in newspaper reports since the murder.

He said: