Image source, Jeff Moore/GlobalImage caption, Marr said his new LBC programme will give him "more freedom"
Andrew Marr is to leave the BBC after 21 years to "get my own voice back", he has announced.
He joined the broadcaster as political editor in 2000 and has presented a Sunday morning programme since 2005.
He will host an "opinion-led programme" on radio station LBC, a new show on Classic FM, and write for newspapers.
He said UK politics and public life "are going to go through an even more turbulent decade, and as I've said, I am keen to get my own voice back".
In a statement from LBC and Classic FM's parent company, he said: "Coming to Global gives me a new freedom – to do fast-paced, very regular political journalism on LBC with no filter, in entirely my own voice."
Image caption, The Andrew Marr Show has been on air since 2005
At the BBC, director general Tim Davie has said his top priority is impartiality, with presenters reminded not to air their personal political opinions.
Marr's departure comes weeks after culture secretary Nadine Dorries questioned his impartiality following his interview with Prime Minister Boris Johnson.
"Well, there is literally nobody on this little blue planet who doesn't have opinions," Marr responded in an article in The Spectator.
"At the BBC we do our level best to leave them at the door but if you don't have some opinions you aren't thinking, and if you aren't thinking, how useful a political interviewer could you be?"
Image caption, Marr was BBC political editor from 2000 to 2005
Davie said Marr had been "a brilliant journalist and presenter during his time at the BBC".
He said: "He leaves an unmatched legacy of outstanding political interviews and landmark programmes. We wish him well for the next chapter."
BBC director of news Fran Unsworth described him as a "fantastic presenter and interviewer, whose wisdom and skill will be a loss to our screens".
Marr wrote on Twitter that he will "leave behind many happy memories and wonderful colleagues".
"But from the New Year I am moving to Global to write and present political and cultural shows, and to write for newspapers."
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He added: "I have been doing the Andrew Marr show every Sunday morning for 16 years now and that is probably more than enough time for anybody!"
Marr, who also co-hosts BBC Radio 4's Start the Week, began his journalism career in the press, including as editor of The Independent in the 1990s.
Global executive president Ashley Tabor-King described him as "one of the finest and most respected broadcasters and journalists of our time".
He said: "LBC now takes its next step. Andrew Marr will be an unmissable moment in the schedule and we are excited that he will be part of LBC and Classic FM's incredible presenter line-up."
The presenter had a stroke in 2013, and earlier this year spoke about his experience of catching Covid, probably at the G8 summit in Cornwall, despite being double vaccinated.