Sentencing Rakesh Bhayani for the murder of Carole Waugh, Mr Justice Wilkie said he "ruthlessly targeted" Ms Waugh and "left her body to rot".
He said the murder and subsequent dumping of the body was done with "greed, callousness and total lack of any regard" for her.
The murder was "arising out of an argument about money", and the judge described Ms Waugh as a "risk-taker and manifestly vulnerable to conmen".
He said: "Without a second thought, you calmly and comprehensively set about stealing her identity.
"You took steps to ensure her body would not be found for a sufficient time."
Mr Justice Wilkie said Bhayani embarked on the complete "asset-stripping of her persona".
Ms Waugh's family were in court for the sentencing and heard the murder was "not premeditated or pre-planned".
Conman Rakesh Bhayani has been jailed for life with a minimum term of 27 years for murdering wealthy Carole Waugh, dumping her body in a car and spending her money.
Police described Bhayani as "a confidence trickster who murdered her with the sole intention of stripping her assets and the belongings she had worked hard for".
A conman has been found guilty of murdering a wealthy woman who was stabbed to death in her flat and whose body was hidden in the boot of a car. 41-year-old Rakesh Bhayani was convicted of killing Carole Waugh.
Co-accused, Nicholas Kutner, was found not guilty of murder but guilty of perverting the course of justice by concealing the death.
Co-accused Nicholas Kutner, 48, was found not guilty of Carole Waugh's murder by a jury at the Old Bailey, but guilty of perverting the course of justice by concealing the death.
He had already admitted conspiracy to defraud.
Carole Waugh, 49, died at her flat in Marylebone, central London.
Her body was placed in a bag, which was carried to a car. The vehicle was initially stored in a central London car park, then left in a rented garage in New Malden, south London.
Rakesh Bhayani was today found guilty at the Old Bailey of the murder of wealthy Carole Waugh who was stabbed in the neck in her flat in Marylebone, central London.
Nicholas Kutner was found not guilty of murder.