Sir Cliff Richard, Ms Dando's childhood heart-throb, was among those speaking warmly of the Crimewatch and holiday presenter, as well as performing a touching song This Love.

Cliff Richard performed the song This Love at the service

In a tribute to Ms Dando contained in the leaflet given to those attending the service, her former Crimewatch partner Nick Ross said: "Maybe she was just too good to last.

"Beauty without self-consciousness, fame without swagger, popularity which bemused her. But this was no fairy story. She was not born to success."

The BBC's Nicholas Witchell reports on the service of thanksgiving at All Souls Church

The London service in a church decked with sunflowers, is designed as a positive celebration of her life.

It is taking place just three days after she was due to marry fiancé Alan Farthing.

Dozens of on-lookers gathered outside All Souls Church, next to the BBC's Broadcasting House, as guests lined up to enter.

The former BBC sports presenter Des Lynam attended the service

Among the guests was her friend, the broadcaster Carol Vorderman, BBC newsman John Simpson, sports presenter Des Lynam and former BBC political editor John Cole and BBC director-general, Sir John Birt.

Sir John gave the main address at the service.

He paid tribute to Ms Dando's "passionate determination" and complete professionalism.

He said: "She was adored by everyone she worked with. She was never grand. She mucked in as part of the team."

"She was a beauty - a true English rose. But it wasn't just her physical beauty that beguiled.

BBC's Sir John Birt: "It wasn't just her physical beauty that beguiled"

"When Jill's eyes lit up, or when she flashed that lovely, dazzling smile, it was the character within that was illuminated."

Also paying tribute to Miss Dando and giving the readings were Sir Paul Condon, Commissioner of the Metropolitan Police, BBC Royal Correspondent Jennie Bond, and ITV Sport presenter Bob Wilson.

Mr Farthing, Ms Dando's brother Nigel and father Jack were also at the service.

Sir Cliff Richard talks about his feelings after the service

Ms Dando was shot dead at her home in Fulham, West London, in April, but detectives have been unable to track down the killer despite nationwide pleas.

Countess of Wessex was among those attending

Alan Farthing said: "Jill inspired millions with her beautiful smile and vivacious personality. We miss her desperately but today is the opportunity to give thanks for her life and all she achieved."

A new research award named after Jill Dando was also announced on Tuesday by the British Heart Foundation.

The TV presenter was born with a heart defect and was a major supporter of the charity.

Crimewatch partner Nick Ross made a tribute in the service booklet

The first Jill Dando Fellowship has been awarded to Dr Mike Mullen of the Great Ormond Street Hospital in London.

He will use the award to fund his research into adults living with congenital heart defects.

A spokesman for the BHF said: "We hope that helping to support and train one of the most promising new researchers in this field is an appropriate way of recognising the major contribution she made to our work."