Police are appealing for witnesses after two men assaulted a petrol station employee and made off with £30,000.
The 45-year-old employee was collecting the weekend's takings from the Murco garage in Bishopsford Road, Morden, at 9.55am on Monday when police said he was hit over the head with a blunt object.
Police said the injured employee was then sprayed in the face with what is believed to be CS spray by the second man.
The suspects then grabbed the bag of cash and took off.
The robbers fled the scene in a black Volkswagen Golf parked in Wandle Road and drove off along Bishopsford Road towards Sutton.
London Ambulance Service rushed the employee to a west London hospital where he was treated from minor injuries. He has since been discharged.
The robbers are described as black or Asian men, about 5 ft 10 ins tall, of slim build and wearing motorbike helmets and high visibility jackets.
Anyone with any information about this incident are asked to contact Merton police on 020 8649 3039 or to remain anonymous call Crimestoppers on 0800 555 111.