"Twelve fire engines and around 80 firefighters have been called to a fire at a school on Hewett Road in Dagenham. Around half of the single-storey building is currently alight," the firefighters said in a statement.
The cause of the fire is not known, and there have been no reports of injuries so far. According to a statement on the school's web site, classes had been set to commence on Wednesday.
The town is part of the London Borough of Barking and Dagenham, about 9 miles east of the center of London.