Copper thieves left gas pipes dangerously exposed and leaking gas over the weekend in New Malden.
A firefighter at New Malden fire station said a copper pipe had been stolen from the outside of a house in Burlington Road in the early hours of Monday morning.
The same thing happened hours later near New Malden station.
Firefighters blocked the leaks with putty before turning the mains off and calling the power company.
He said: "If it is gushing out into thin air it is not that dangerous. The risk of explosion is not huge but it is costing a lot of money."
Police were called to both incidents, he said.
Councils across the country have warned of the risk of explosion and fires as copper thieves target restaurants and homes.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here