Dennehy, 33, had claimed being placed in solitary
confinement violated her human rights and took her case for damages to the high
court.
But judges ruled it was "necessary and
proportionate" to place her in solitary confinement after hearing that a
detailed escape plot, involving murdering a female guard and taking her keys
and using her fingerprints, was discovered in her cell.
A written plan was located in her cell with detailed plans
involving killing a female officer to obtain her keys and to utilise her finger
prints in order to deceive the biometric systems.
Justice Department barrister Tom Weisselberg QC
Dennehy was given a whole-life sentence at the Old Bailey
for murdering three men and stabbing two more.
She claimed that she had been left "tearful and
upset" after being placed in segregation at HMP Bronzefield near Ashford,
Surrey, since prison guards allegedly found a breakout plot in her diary.
Government lawyers have conceded the segregation period
between September 21 2013 and September 4 2015 was technically unlawful because
it was not properly authorised by former Justice Secretary Chris Grayling.
But Mr Justice Singh, sitting in London, ruled that her
segregation since then had been "in accordance with law" and "at
all material times it has been necessary and proportionate".
Justice Department barrister Tom Weisselberg QC told the
High Court that a credible escape plot was found in her cell.
"Dennehy was segregated because a credible escape plan
involving her and two other prisoners had been uncovered," he said.
"A written plan was located in her cell with detailed
plans involving killing a female officer to obtain her keys and to utilise her
finger prints in order to deceive the biometric systems.
"She was placed on the escape list, which involved the
wearing of an escape suit."
Dennehy was given a whole-life term after admitting the
murders of Lukasz Slaboszewski, 31, Kevin Lee, 48, and John Chapman, 56, whose
bodies were found in ditches in and around Peterborough in 2013.
She also pleaded guilty to two counts of attempted murder in
Hereford and preventing the lawful and decent burial of her murder victims.
Dennehy, of Orton Goldhay, Peterborough, claimed at London's
High Court that she has been "unfairly and unlawfully" held in
segregation at HMP Bronzefield.
Hugh Southey QC argued at a hearing in March that her
incarceration violated her human rights and had taken a heavy toll, leaving her
"tearful and upset", and at times she was resuming her practice of
self-harming.
Mr Southey described Dennehy, who was jailed in February
2014, as a "vulnerable" inmate due to her history of severe
personality disorders, and episodes of self-harming dating back to childhood.
Government lawyers said the segregation was fair, justified
and lawful due to the nature of Dennehy's offending and the escape risk she
poses.
They submitted there was also no procedural unfairness
during her continued segregation after September 2014.
Jenni Richards QC, appearing for HMP Bronzefield, described
Dennehy as "arguably the most dangerous female prisoner in custody".
Dennehy "got a taste for killing" and had admitted
to the psychiatrist that she was "sadistic".
Mr Southey submitted there was unfairness because the escape
allegations were never properly put to Dennehy at the time.
She insisted that the alleged plot was nothing more than a
"doodle" found in her diary, said Mr Southey.
The police had investigated the claims and "confirmed
that no further action would be taken".
Dennehy is only the third woman to be given a whole-life
prison term. Moors murderer Myra Hindley and House of Horrors serial killer
Rose West are the other two.
