26 year old Ismail Tajzai pleaded guilty to robbery, attempted robbery and two counts of having an imitation firearm with intent to commit robbery.
He also pleaded guilty to making a threat to kill, strangulation and perverting the course of justice.
He was sentenced to 14 years in jail and a restraining order was put in place banning him from contact with the two victims.
Detective Constable Stephanie Clarke, of the Westminster Public Protection team, said: “This case demonstrates the support police will offer to all victims of crime in order to prosecute violent, dangerous men.
“The defendant sought to exploit vulnerable sex workers, and deliberately aimed to commit crimes against a group of people whom he assumed were scared to report crimes to police.
“I had first-hand experience during the investigation of how scared the victims were to report to police, out of fear of repercussions that could be caused to them. I would urge anyone else who has been the victim of similar crime to contact police and an investigation will be launched with specialist support for the victims.”
Detective Inspective Luke Bacon, of the Westminster Public Protection team, said: “I would like to commend my officers for their dedication in identifying this particularly dangerous individual and the swift action they took to ensure his arrest and prosecution. This was a time-sensitive investigation, and I firmly believe that if it were not for the actions they took, more attacks would have occurred.
“I would also like to reserve particular praise for the victims involved in this terrifying case. They showed immense bravery in coming forward to report to the police in the first instance, and in doing so they have ensured that this dangerous individual was caught, prosecuted and convicted.”