CCTV footage of the robbery outside Sainsbury’s in Lyon’s Farm has been released by police.
On Tuesday (March 8) two men approached the driver of a Loomis security van, threatened him and stole a cash box, before driving away in a blue Ford Mondeo followed by a black Subaru Impreza.
Loomis is now offering a £5,000 reward for the arrest and charge of those responsible.
The Mondeo was abandoned and set on fire just before the junction of Northbrook Road and Leighton Avenue.
The men were seen running to the waiting Subaru that had stopped in Northbrook Road.
CCTV cameras captured the two cars passing and the resulting plume of smoke after the Mondeo was set alight.
The security van driver received severe bruising and was taken to Worthing Hospital for treatment. Another security guard attempted to intervene. He was shaken but uninjured.
One of the suspects is described as white, 30 to 40-years-old, 6ft to 6ft 3in, of stocky build with a round face. He had stubble which was light or grey flecked in colour. He had a local or London accent and was wearing a black baseball cap and black shell-suit type jacket, dark blue trousers and trainers which were dark with white colouring.
The other man was slightly younger and slimmer. He was also white, between 5ft 7in and 5ft 9in, wearing a black woolly hat dark jacket with dark, possibly olive green trousers and dark trainers.
No weapon was seen or mentioned during the robbery.
Anyone with information is asked to contact Worthing CID on 0845 60 70 999 quoting Operation Convoy or anonymously to the independent charity Crimestoppers on 0800 555 111
To view the footage, click on the link at the side of this page.