Shocking CCTV shows the victim attacked at his work desk and wrestled to the ground before the men flee with his gold watch.
14:09, UK, Thursday 18 February 2016
A pair of thugs burst into a man's office and choked him unconscious before snatching a gold watch from his wrist.
The footage shows the robbers grab him as he sat at his desk, put him in a headlock and wrestle him to the floor before escaping with his £15,000 Rolex Yacht Master.
The thieves ran out of the shop and were driven away by a woman and third man in a black Peugeot 206.
Police have warned the public not to approach either of the men if they spotted.
The second is also white, aged 38 to 40, of medium build with a "scarred complexion".
Detective Constable Andrew Payne, of the Metropolitan Police, said: "We believe the victim was targeted by the suspects to steal his watch."
Anyone with information can call the police on 020 8284 9449 or Crimestoppers anonymously on 0800 555 111.