The youngest woman convicted of plotting a terror attack on British soil has been jailed for life with a minimum of 13 years.
Safaa Boular, 18, became the final member of Britain's first all-woman terror cell to be imprisoned when Judge Mark Dennis QC sentenced her at the Old Bailey on Friday.
She hid her Islamic State-inspired plans in coded conversations about preparations for an innocent Mad Hatter's tea party after being seduced online by a jihadi fighter while sitting her GCSEs.
Judge Dennis rejected claims she had entirely renounced her Islamist views and downplayed the extent grooming played in her radicalisation.
"In my view there's insufficient evidence upon which it would be safe to conclude at this stage that the defendant is a truly transformed individual and the serious risk that she has posed hitherto has now evaporated," he said.
"Her views were deeply entrenched. However much she may have been influenced and drawn into her extremism, it appeared she knew what she was doing and acted with open eyes."
Boular was inexpressive as she was jailed for two counts of preparing terrorist acts, which she was found guilty of at a trial.
She had been lured in by IS fighter Naweed Hussain, originally from Coventry, but was prevented from joining the 32-year-old who she purported to marry in an online ceremony. He was later killed in a drone strike.
Instead of committing a terror attack in Syria, she discussed a grenade and gun attack on the British Museum and played what the judge called a "leading role" in an "advanced plan".
But online MI5 role-players uncovered their plans and the Boular family home in Vauxhall, south London, was bugged.
While in custody for trying to travel to the war zone, she passed the baton to her older sibling Rizlaine, 22.
And, in coded telephone calls, they discussed a traditional English tea party with an Alice In Wonderland theme.
Rizlaine Boular set about arming herself and scouting out targets around the Palace of Westminster, all the while being aided by her mother Mina Dich.
The older sister shared her plans with Khawla Barghouthi, 21, and even practised the knife attack at the friend's home in Willesden, north-west London.
Defending Safaa Boular, Joel Bennathan QC said she had been "groomed" into radicalism when she was 15 but has now shunned Islamist extremism and no longer follows the Muslim faith.
"The environment in which this young woman became drawn into radical Islamist terrorism was a family which had the combination of a neglectful mother and an older, very radicalised sister," he said.
The defendant is "no longer that type of person", he argued.
"That's the point about teenagers, they can change dramatically and fast," Mr Bennathan added.
"She was a child, she was 15, when this started."
After her arrest on April 27 last year, Rizlaine was jailed for life with a minimum term of 16 years, having admitted preparing acts of terrorism.
Dich, 44, was imprisoned for six years and nine months with an additional five years on licence for helping her.
Barghouthi, who pleaded guilty to failing to alert authorities, was jailed for two years and four months.