Four teenagers have been arrested in connection with the fire at the Darul Uloom School in Chislehurst over the weekend.
According to a statement released by the Metropolitan Police, the four males - two aged 17 and two 18 - were arrested on suspicion of arson late on Sunday night, before being taken into custody at a south London police station.
The fire occurred on Saturday evening [8 June], resulting in the evacuation of 128 pupils and staff, and minor damage to the school building. Two people were also treated for smoke inhalation.
Prior to the arrests Metropolitan Police Commissioner Sir Bernard Hogan-Howe said: "These are difficult times for London's communities. The Met is now investigating suspicious fires at two locations which have happened in the past few days. Fortunately no one has been hurt, but we know that fires can often prove fatal.
"I want to reassure people that we are using our full range of policing tactics to protect sites that might be vulnerable. In all boroughs across London, there is an increased police presence around locations that might be at risk. We will maintain a 24/7 guard of uniformed officers at sites we consider to be at greatest risk.”
Police are asking members of the public to remain calm and not to speculate as to the cause of the fire.