British Transport Police have confirmed that gas canisters were used in an attempted theft from a cash machine at Thornton Heath rail station this morning.
BTP and officers from the London Fire Brigade attended the scene and made the canisters safe after the incident was reported shortly after 4am.
Detective Inspector Andy Rose, of BTP CID, said: "The station booking hall was broken into and the ATM inside was badly damaged in what we believe was an attempted theft.
"However, the assailants were disturbed at 4am and left the scene empty-handed.
"When our officers arrived they found the ticket office had been broken into and gas canisters had been used as part of an elaborate attempt to break open the cash machine."
Detectives are examining CCTV footage from the booking hall and outside the station, while crime scene investigators are searching the station for evidence.
DI Rose added: "We believe two men were involved in the incident. The first is described as white, in his 40s, 6ft 2in, slim build, wearing a yellow high visibility jacket, orange high visibility trousers and a black scarf around his face.
"The second man is described as 5ft 8in, slim build, wearing a blue jacket, blue jeans and black balaclava."
"We want to hear from anyone who noticed any suspicious activity in the area, or has any information that could assist us in our investigation."
Anyone with information is asked to contact British Transport Police on 0800 40 50 40 quoting incident SSUB/B6 of 03/06/2014. Alternatively, call Crimestoppers on 0800 555 111.
