Hundreds of people were evacuated from their homes as police warned of a "huge" gas leak.
Four reception centres were set up for residents to shelter from the cold as gas engineers worked to fix the problem. Around 500 were told to leave, according to the BBC.
Police, firefighters and ambulance crews were sent to Queen Adelaide Road in Penge, south-east London, shortly before 11pm on Saturday.
Sergeant Lance Chenery from the Bromley neighbourhood policing team described the evacuation as "large".
He said on Twitter: "On scene with MPSBromley dealing with a serious gas leak in Penge SE20 large evacuation of residents."
A Metropolitan Police spokesman said road closures were put in place as a cordon was set up around the site, but residents had been allowed back into their homes at around 5am.
Shortly after the alert Bromley MPS tweeted: "Huge Gas Leak Penge Lane/Queen Adelaide Road. Houses being evacuated. Please avoid this area.
"Road closures remain in place in Penge ... 4 reception centres housing evacuees. Community spirit pulling through."
Once the incident had been cleared up, the police account tweeted: "Delighted but cold residents start returning to their homes in Penge ... Christmas slippers coming in useful!"