L'Anson is to leave the station after what has been called an "amicable" agreement.

Theakston, 27, will present her Sunday lunchtime show from 1300 to 1500 from 4 April. He joins his co-host from Live & Kicking, Zoe Ball, at the station. She already presents the weekday Breakfast Show.

Theakston said: "I love music and Radio 1 is such an exciting station. To get the chance to play great music to a large audience on Sunday afternoons is an excellent opportunity."

L'Anson moves on

Lisa l'Anson: Looking for more TV work

Lisa l'Anson said of her departure: "After more than four years at Radio 1 I have decided the time has come to for me to move on.

"There have been many changes while I have been at the network and I'm proud to have played a part in establishing it as the UK's leading music station," she said.

Last year she landed herself in trouble by failing to turn up for a live broadcast from Ibiza after spending the night in a club on the island. She was given a final warning and forced to make a public apology.

Her agent, John Noel, said she would be expanding her television work, and was thinking about working in the US.

Theakston's 'natural home'

Jamie Theakston began his broadcasting career on radio reading sport and traffic bulletins on London's local BBC radio station GLR and later BBC Radio 5 Live.

He then went on to work on pop show The O-Zone and has regularly fronted BBC One's Top Of The Pops.

He has already experienced working on Radio 1 as a stand-in for Jayne Middlemiss on the Sunday afternoon Top Of The Pops radio show.