A handgun-wielding robber demanded cash from staff at a bank in Mill Hill.
The raider walked into the Lloyds TSB bank in Mill Hill Broadway at around 11.50am and demanded money from staff.
The robber, who was male and wearing a crash helmet, made off with a small quantity of cash.
No shots were fired and there are no reports of any injuries.
Anyone with information should call Crimestoppers on 0800 555 111.
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