A young woman who knew about her friend's imminent plot to launch a knife attack on Westminster has been jailed for two years and four months.

Khawla Barghouthi, 21, also faces deportation to Tunisia after she admitted failing to disclose Rizlaine Boular's Islamic State-inspired plan to authorities.

Boular, 22, had discussed and even practised her proposed knife attack at Barghouthi's home in Willesden shortly before her arrest on April 27 last year.

In a bugged conversation, the women were heard laughing as Boular talked about her fears that she might "flop so badly" and cut her arm by accident.

Khawla Barghouthi, 21, who has been jailed for two years and four months

When armed police swooped to arrest them, Boular shouted "F*** you" and was shot by an officer, who thought she had something in her hand.

In mitigation, Michael Mansfield QC said Barghouthi came to Britain at the age of 11 from Tunisia knowing no English but excelled at school and aspired to a caring profession.

When she met "disturbed" Boular, she lent her a "hand or a shoulder", not knowing how serious she was, he argued.

Of her banter with Rizlaine on the day of the planned attack, married Open University student Barghouthi said: "I did not believe the person I was with was actually going to go through with anything.

"When I read the transcript I was horrified how it sounds. What I can say, at the time it was extravagant talk and very stupid fooling around."

But passing sentence at the Old Bailey, Judge Mark Dennis QC said the defendant knew Boular was serious and did nothing to alert authorities or put her off.

He said she "failed to disclose information about an imminent attack in which a knife would be used to endanger the life of multiple individuals".

He said: "There was a growing awareness over a number of days of the nature of the attack by Rizlaine Boular."

He added: "There is no reason, in my view, to doubt that Rizlaine Boular intended to carry out her violent action, even at the cost of her own life."

The recorded conversation showed Barghouthi did believe her friend intended to go ahead with the violence and yet did nothing to put her off, the judge said.

He also noted Barghouthi's interest in extremist material, although it was a "comparatively small amount".

Safaa Boular is Britain's youngest terror plotter

Last Friday, Rizlaine Boular was jailed for life with a minimum term of 16 years, having previously admitted preparing acts of terrorism.

Her mother, Mina Dich, 44, from Vauxhall Cross, south London, was jailed for six years and nine months with an additional five years on licence for helping her.

The court heard that Boular took up the mantle from her younger sister, Safaa, who had planned to attack the British Museum after her Islamic State fiance was killed in Syria.

The sisters had discussed it in coded chat about an Alice in Wonderland-themed tea party.

Safaa Boular, 18 - Britain's youngest female IS terror plotter - will be sentenced at a later date after she was found guilty of preparing terrorism in the UK and Syria.