A number of schoolchildren had to be rescued after a watermain burst overnight and flooded several homes, leaving people trapped.
About 70 firefighters are at the scene in Blackheath, southeast London, after the alarm was raised at around 4am.
At least six homes were flooded in the area as well as the nearby Lee Green Fire Station on Eltham Road, with crews helping people escape the flood water on board rubber dinghies.
A spokesman for London Fire Brigade said: "Ten fire engines and around 70 firefighters dealt with flooding on Meadowcourt Road in Blackheath and Eltham Road.
"Crews diverted flood water and assisted residents to safety after a water main ruptured, flooding an area of around 600m x 200m to a depth of around 50cm.

"Six properties were flooded and the fire station was also affected by flood water. There were no reports of any injuries.
"There are significant road closures still in place and buses are being diverted. People are advised to avoid the area.
"The Brigade was called at 0438 and the incident was over for firefighters by 1006. Fire crews from Lewisham, Eltham, East Greenwich and surrounding fire stations attended the scene. "

Among the homes affected were three basement flats where water levels rose to around 20cms.
Nearby Blackheath High School has had to close for the day because of the nearby flooding issues.
They tweeted: "There is a major Thames Water flood affecting the surrounding area and our school.

"Both Junior School and Senior School have unfortunately had to close. Please see Firefly communications for action required. Thank you."
Thames Water confirmed it was working to fix the issue "as soon as possible".
In their latest update they said: "Although some customers are still without water, the situation should be improving for many people whose supply was affected by a large burst pipe in Eltham Road, SE12.
"Our supply network is starting to refill, and we’re working to get things back to normal as soon as we can. We’re really sorry to anyone affected by this.

"We’d also like to apologise to drivers affected by the closure of the A20."
In an earlier tweet the firm added: "We’re really sorry if you’ve been affected by a large burst pipe on the A20 Eltham Road.
"We’ve shut off the flow from the damaged section and are working to get things back to normal as soon as possible."
People have been advised to avoid the area while busses have been diverted.