A robbery and an attempted robbery at two betting shops on the same day have been linked by police.
Officers were first called to reports of an attempted robbery in Blackbird Hill, Kingsbury, at 3.30pm yesterday.
A man had entered the shop threatening staff with a knife before leaving empty handed.
Then at 5.28pm a man entered the Ladbrokes betting shop in Grand Parade, Forty Lane, Wembley.
He handed staff a note demanding money while holding a black plastic bag indicating there was a weapon in it. No weapon was seen.
The member of staff handed over cash to the man before he left. Nobody was injured and there have been no arrests.
Detectives from the Flying Squad investigating the crimes have linked them and are calling for anyone with any information to get in contact.
The man from the incidents is described as white, between 40 and 45 years of age, between 5ft 5ins and 5ft 8ins tall and with a stocky build.
He was seen wearing a dark hooded, combat-style jacket, light, grey jogging bottoms and white trainers.