A Potters Bar woman who shouted encouragement as her boyfriend stabbed her ex-lover to death was jailed for three years today.

Kelly Sanchez, 21, of Mutton Lane, Potters Bar, cried in the dock at St Albans Crown Court as Judge Michael Baker QC passed a mandatory life sentence following her conviction for the murder of father-of-two John Redhead, 40.

However, he imposed a minimum sentence of just three years and she can be released on parole after that term.

Sanchez's boyfriend Mark Russell, 41, of Chester Close, Potters Bar was also convicted of murder last month and sentenced to a minimum of 14 years in jail.

The court heard that the attack, on August 26 last year, was motivated by sexual jealousy. Mr Redhead had broken up with Sanchez three weeks before his death when he discovered that she was cheating on him.

She then began a relationship with Russell, who was described by Mr Baker as a "malign, evil influence."

Sanchez maintained that she was still in love with the victim and had met him in a Potters Bar pub on the night of the attack, but she began rowing with his friend John Darling.

After the argument she met Russell and drove to the flat shared by Mr Darling and Mr Redhead, in Barnet Road, Potters Bar, where they lay in wait for the men to return before launching their assault.

Russell approached Mr Redhead and stabbed him four times with a kitchen knife while Sanchez shouted encouragement. The final blow was so hard that the knife was left lodged in his arm.

Mr Baker emphasised the significance of the role played by Sanchez, saying she "aided and abetted the commission of a murderous attack."