Serial killer Joanna Dennehy plotted to escape jail by using the severed fingers of guards to open fingerprint locks

Joanna Dennehy is serving a whole-life sentence for murdering three men in Peterborough in 2013

(PA)

Serial killer Joanna Dennehy plotted to escape from prison by murdering a guard and using their severed fingers to unlock biometric doors, it has been revealed.

Ms Dennehy, 33, described in court as “the most dangerous female prisoner in custody”, is serving a rare whole-life sentence for the murder of three men in Peterborough in 2013.

“A written plan was located in her cell with detailed plans involving killing a female officer to obtain her keys and to utilise her fingerprints in order to deceive the biometric systems,” barrister Tom Weisselberg told the High Court on Thursday.

After details of the plot were found written in a diary, Ms Dennehy was placed in solitary confinement at HMP Bronzefield, near Ashford in Surrey, where she has been imprisoned since February 2014.

“Dennehy was segregated because a credible escape plan involving her and two other prisoners had been uncovered,” said Mr Weisselberg.

Ms Dennehy filed a High Court damages claim for human rights violations she said she suffered during more than two years of solitary confinement.

But the court rejected her claim, ruling her continued segregation since then as “necessary and proportionate” and “in accordance with the law”.

She was denied any payout.

Lukasz Slaboszewski, left, and John Chapman were both victims of Joanna Dennehy (PA)

The prison’s barrister Jenni Richards said Ms Dennehy “got a taste for killing” and had told a psychiatrist that she was “sadistic”.

After killing her third victim, she phoned a friend to sing the Britney Spears song “Oops… I Did It Again” and danced a jig of delight when she saw a television news report about the killings, which took place over two weeks.

She also attacked two other men and left them for dead, telling John Rogers, who survived his wounds, “Oh, look you’re bleeding. I’d better do some more”.

Ms Dennehy had been left “tearful and upset” and at risk of self harm by the decision to isolate her from other prisoners, which was not properly explained to her, argued lawyer Hugh Southey.

Government lawyers conceded her segregation period between 2013 and 2015 was technically unlawful, because it was not properly authorised by former Justice Secretary Chris Grayling.

Mr Southey said Ms Dennehy was a “vulnerable” prisoner due to her history of severe personality disorders, who insists that the alleged plot was nothing more than a “doodle”.

Ms Dennehy pleaded guilty to the murders of Lukasz Slaboszewski, 31, Kevin Lee, 48, and John Chapman, 56, whose bodies were found in ditches in and around Peterborough.

She also admitted two counts of attempted murder in Hereford and preventing the lawful and decent burial of her murder victims.

Ms Dennehy is only the third woman to be given a whole-life prison term, along with Myra Hindley and Rose West.

Additional reporting by Press Association