The trust has a network of 700 personal safety trainers and tutors

Paul Lamplugh said no-one had forgotten the 25-year-old estate agent, but she would have wanted them to "move on".

He said he was grateful to have had the chance to make a difference through the Suzy Lamplugh Trust, set up by the family to promote personal safety.

Miss Lamplugh disappeared while showing a client a house in Fulham. In 1994 she was declared dead, presumed murdered.

Twenty years to the day of her disappearance, Mr Lamplugh told the BBC: "When Suzy disappeared and we had no idea what had happened, it was immensely traumatic. I remember Diana [Suzy's mother] saying she felt on fire.

What I have always wanted to do was to do my little bit to change the world... I'm grateful to Suzy, I suppose, and certainly to Diana, that I have had my opportunity to do just that Paul Lamplugh

"As time went on, as far as our other children were concerned, it was important for them that they moved on with their lives.

"None of us has forgotten Suzy and what a lovely person she was.

"But I just know Suzy would have said: 'Come on mum and dad, come on everybody, you have done what you can, get on with your lives' and that's what we've done."

He said running the Suzy Lamplugh Trust had become such a big part of the family's lives, it was hard to imagine the past 20 years without it.

"What I have always wanted to do was to do my little bit to change the world... I'm grateful to Suzy, I suppose, and certainly to Diana, that I have had my opportunity to do just that."

Diana Lamplugh was awarded an OBE in 1992

Mrs Lamplugh had to step down from the charity after being diagnosed with Alzheimer's disease.

Her husband also stepped down in order to look after her. Both have been awarded OBEs for their work with the trust.

Mr Lamplugh added: "I think one of our greatest achievements is that we have created the discipline of personal safety... and every self-respecting organisation in this country now has a personal safety policy."

The trust now has 16 staff and a network of more than 700 personal safety trainers and tutors throughout the UK.

'Mr Kipper'

Miss Lamplugh left the estate agency to show a property to a man calling himself Mr Kipper in July 1986. She was never seen again.

A massive hunt was started, but by October 1987 the police investigation was scaled down.

The file remained open and throughout the years several convicted murderers were linked with the death but all theories were discounted by the police.

The most recent searches for her body took place in 2001 when police searched a site close to Norton army barracks near Worcester, and then in the Quantock Hills, in Somerset.

In 2000, the police reinvestigated the Lamplugh case when they received new information but there was not enough evidence to prosecute anyone and the case was closed.