Carshalton PCSO Mario Palermo was on patrol at 10:50hrs on Sunday, 8 November when the alarm went off at Goodfellows in Beeches Avenue, Carshalton. PCSO Palermo looked through the estate agency front window and saw two males - one of them trying to smash the alarm off the wall inside.
The males fled the building and drove off in a silver car - leaving behind the £100 proceeds of a charity fundraiser in the building from the night before.
PCSO Palermo radio'd for assistance immediately from other police officers relaying the suspect's descriptions and their vehicle registration number.
The suspects are described as white males of Eastern European appearance aged in their late 30s or early 40s. Enquiries are continuing. If you have any information to help, contact Sutton Police station on 101. Alternatively, call Crimestoppers anonymously on 0800 555 111.
PCSO Palermo said: "I just happened to be in the right place at the right time. I'm really glad they didn't take the charity money." A female member of staff at Goodfellows estate agents said: "He's our hero."