A 16-year-old boy has been charged with arson following a fire at the London Oratory School in west London on Wednesday morning.
Ten fire engines and 70 firefighters were called to battle the blaze in the atrium of a four-storey building on Seagrave Road in Fulham.
A teenage boy was arrested a short time later and has been charged with arson.
He is due to appear in custody at Highbury Youth Court later on Friday.
The fire was brought under control and no injuries have been reported.
But part of the atrium was damaged, the London Fire Brigade said. Fire crews from Fulham, Chelsea, Kensington, Wandsworth, Hammersmith, Clapham, Lambeth and Soho fire stations attended the scene.
The secondary school admits boys aged seven to 18 and girls aged 16 to 18.
Alumni from the 160-year old Catholic school include actor Simon Callow, trade unionist Mick Whelan as well as the children of the former prime minister Sir Tony Blair, of Harriet Harman and of former deputy prime minister, Sir Nick Clegg.