Lawley described it as "one of the best jobs in broadcasting"

She said she wanted to pursue "other aspects of broadcasting and maybe a bit of business too".

The broadcaster has hosted the show since 1987 and is only the third presenter in the popular programme's 64-year history.

Her last programme will be broadcast on 27 August. The BBC said no decision has been made about her replacement.

She will be a tough act to follow Mark Damazer, Radio 4 controller

Lawley said: "I've had more than 18 very happy years and have talked to some extraordinary people as they revealed themselves through their choice of music.

"It is one of the best jobs in broadcasting. But it has dominated my professional life and I feel the time has come to concentrate on other aspects of broadcasting and maybe a bit of business too."

Desert Island Discs was devised in 1942 by Roy Plomley, who presented the programme until his death in 1985.

Tony Blair appeared on the show in 1996

Michael Parkinson succeeded him and Lawley took over in 1987.

The simple format of the programme sees guests, or "castaways", choose the eight records they would take with them to a desert island.

Lawley has attracted some of the biggest names in politics, the arts, literature, science and sport, and the show has offered many unexpected insights into their lives.

Mark Damazer, Radio 4 controller said: "I tried hard to persuade Sue to change her mind but to no avail.

"She started her career as a journalist and is still a journalist at heart. She also has an enormous interest in people.

"Put these two attributes together and you end up with fascinating and entertaining interviews that are now the hallmark of Desert Island Discs.

"She will be a tough act to follow."

The BBC said "no decision has been made as to who will replace her".