An all female Isil gang plotted to murder tourists at attractions including the British Museum, a court has heard.

Safaa Boular, then 17, planned to "martry" herself in a bomb and grenade ambush on the museum after her Islamic State fighter fiance was killed in Syria.

In what is alleged to be Britain's first all female terror plot, she was supported by her mother, Mina Dich, and elder sister and intended to carry out an attack using a 'tokarev', a type of Russian pistol, or a grenade, referred to as 'pineapples'.

But when Boular was arrested for an earlier attempt to travel to Syria to marry Naweed Hussain, she passed the baton to her sister, Rizlaine Boular, who began plotting a knife attack in Westminster.

In calls from jail after her arrest, she talked about a "party" with her 21-year-old sibling, which was said to be a code word for a terror attack which her sister was planning in her place.

The pair also made reference to a "Mad Hatter" and having an "Alice In Wonderland" themed tea party, jurors heard.

Over the next three days, Rizlaine and their mother, 43, carried out reconnaissance around major landmarks in Westminster and bought a pack of knives and a rucksack, the court heard.