A man who committed a series of robberies within days of each other in Slough has been jailed for at least seven years.
Klinton Dunn, 28, of no fixed abode, was sentenced at Reading Crown Court.
He was found guilty of three counts of robbery, four counts of kidnap, and two counts of being in possession of an offensive weapon.
In one robbery, he held a knife against the throat of a young girl who was with her mother, prosecutors said.
Police said he singled out lone women drivers for his attacks.
On three occasions he got into the women's cars, threatened them at knife point and robbed them of cash and handbags between 25 and 29 October in 2010, the Crown Prosecution Service (CPS) said.
Det Con Alex Gresty said Dunn had caused "unimaginable fear" to his victims.
"Klinton Dunn chose to target lone women. One mother was with her young daughter and particularly vulnerable as she sought to protect her," he said.
"In each robbery, Dunn entered the victim's car and, at knife point, he forced the victim to drive to a location where their fate was unknown to them."
Prosecutor Victoria Griffiths said Klinton Dunn was "an extremely dangerous individual".
She said he had carried out the offences of robbery and kidnapping at knife point whilst he was on licence following early release from a seven-year sentence for robberies of two elderly ladies.
The sentence orders Dunn to serve a minimum of seven years before the parole board will consider whether he is no longer dangerous and ready for release.