This is the shocking moment customers stood and watched an armed robber 'pistol whip' an elderly shop worker before forcing him to open his till while holding him by the neck.


CCTV footage captured the dramatic incident which saw two men dressed in tracksuits and crash helmets burst into the shop in Rainham, east London.


The elderly worker, thought to be in his 70s, is seen selling a customer cans of beer when one of the men, dressed in dark clothing, comes round the back of the till and grabs him by the neck.


He is then seen hitting the trembling man in the head with what appears to be a gun and forces him to open the cash register.


The robber grabs a handful of notes and is then seen heading towards the exit. 


Meanwhile the other man is seen guarding the door, but steps aside to let another customer in.