Guest director, Michael Rosen, will be in conversation with journalist Polly Toynbee about his role in this year's event.
It's also expected that the entire programme of events will be revealed in advance for the first time.
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We’re live outside St Mary’s Hospital, Paddington, for the birth of Prince William and the Duchess of Cambridge’s third baby.
The BBC contends there was a ‘legitimate public interest’ in its coverage and is vigorously defending the case.
Southampton's marathon runners worked up a sweat as temperatures touched 20c but there was help on hand to keep them cool.