A dual carriageway was closed overnight after a driver set fire to a car and a speed camera in an apparent bid to erase evidence of a fine.
The speed camera, which could cost up to £20,000, went up in flames after a 4x4 car, parked next to it, was set on fire in St Helier Avenue, near Morden Hall park.
Mitcham fire station watch manager, Ned Alexander, said this type of incident was very common and would often be done to try to erase evidence of speeding.
But he explained: "It's very often a waste of time because a lot of these things are digital and the fine has already been sent to the person's address.
"You are causing that amount of damage just for one small fine.
"These speed cameras cost about £20,000 and that amount will be coming out of our council tax."
Police closed the carriageway just after 1.15am today while fire fighters dealt with the blaze, which was out within 30 minutes.
One lane either side of the carriageway then remained closed while the debris was cleared away.
Buses 80, 157 and 164 were diverted following the incident, but are back to normal now.
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