Prosecutor Duncan Atkinson told jurors at London's Central Criminal Court that Boular planned to "unleash violence and terror in the heart of London" by attacking the world-famous museum. The 18-year-old denies planning acts of terrorism.
Atkinson said after Boular was arrested in April 2017 for trying to travel to Syria, she tried to enlist her 21-year-old sister Rizlaine to carry out an attack. In phone calls from prison, she used code words that referred to an attack as an "Alice In Wonderland"-themed tea party, the prosecutor said.
He said Rizlaine and the siblings' mother, Mina Dich, carried out reconnaissance around major London landmarks and bought a pack of knives and a knapsack. The pair were arrested later the same month. Rizlaine Boular has admitted planning an attack and has pleaded guilty to the charges. Dich is accused of assisting her.