A British teenage girl, romantically linked to a boy sentenced to life over an Anzac Day terror plot in Melbourne, has been given a non-custodial sentence by a UK court.

Key points: 16yo girl was romantically linked to boy behind Anzac Day terror plot

16yo girl was romantically linked to boy behind Anzac Day terror plot Court heard girl had become obsessed with idea of suicide bombing and martyrdom

Court heard girl had become obsessed with idea of suicide bombing and martyrdom Girl told court she accepted she was living in a "fantasy online world" and asked for a second chance

Girl told court she accepted she was living in a "fantasy online world" and asked for a second chance Lawyer says case a "very sad milestone for the court"

The judge handed down an intensive referral order for a period of 12 months.

The 16-year-old pleaded guilty to two charges of possessing information likely to be of use to a person preparing an act of terrorism.

The girl exchanged over 16,000 messages over eight days with the teenage boy who planned the foiled attack, the court heard.

The court heard the teenage girl became obsessed with the idea of suicide bombing and martyrdom.

She sought out a Twitter group and was messaged by people with radical views, the court heard.

But the judge, Khalid Qureshi, said there was a "clear lack of any sophistication" in the girl's actions and "the risk of serious harm was low".

The Manchester court was told the radicalised teen had since accepted she was living in a fantasy online world and asked for a second chance.

"From the letter she wrote the court, and from her comments in court, it is clear that she has spent a considerable time thinking long and hard about her behaviour," Judge Qureshi said.

Analysis: Europe correspondent Barbara Miller This case was a lesson in how one 15-year-old girl can become so quickly and dangerously radicalised. She wrote down a recipe for how to make explosives — not because she had any concrete plans at the time, but because she thought that was the kind of thing people like her should be doing. The girl, the court heard, was emotionally neglected at home and sought solace in her religion and online. She hooked up with a Twitter group espousing radical views, a place where individuals would directly message her, seeking her out. Soon her anger and shame about the deaths of Muslims in foreign wars grew and she became obsessed with the idea of suicide bombings and martyrdom. She downloaded images of people about to be beheaded, of a dead child, of Islamic State symbols and of radical figures, including the head of IS Abu Bakr al-Baghdadi. Then came the contact with a boy a year younger than her but with big plans to incite an attack on this year's Anzac Day parade. Who knows what would have happened in Melbourne and to this girl if the boy had not been arrested in March on an unrelated matter. Analysis of his phone led to the discovery of the plot to attack Australia, and of the blossoming relationship between two radicalised teenagers. The court heard the girl now accepted she was living in a fantasy world. Speaking quietly, flanked by her mother and a female community leader, she told the court she wanted a chance to prove that she was not a terrorist. She came pretty close. The question now is: just how many more are there like her in their teenage bedrooms in the UK and Australia, and how do you reach them before fantasy turns to reality?

The girl's lawyer, Nasir Hafezi, said the case had been a "troubling" one.

"A very sad milestone for the Youth Court," he said.

In a statement, Mr Hafezi said it had highlighted the need for greater guidance and support for young people.

"The lesson here is if we as a society, fail to provide guidance or challenge views which are clearly inappropriate and naive, or we fail to provide those spaces for young people to explore their faith and citizenship, then the consequences may be that some young people will gain what may be described as 'flawed ideas'," he said.

"They could be vulnerable to being misguided by sinister people and messages they come across from the unregulated and dark places which exist in the virtual world of the internet and social media platforms."

The boy was sentenced to a life sentence with a minimum term of five years in jail earlier this month for masterminding a plot to carry out a suicide attack on police officers on a Melbourne Anzac Day parade.

British prosecutors alleged the boy committed his crimes from the bedroom of a suburban home in northern England.

They argued the boy was the planner, coaching a Melbourne man in what weapons to acquire, the strength he would need to carry out a beheading and encouraging him to make a suicide video.

They said he was thoroughly and dangerously radicalised by the time he came into contact with the Melbourne man in March this year.

In late March, British police arrested the boy over threats made to behead teachers.

There was no suggestion that the teenage girl was directly involved in the Anzac Day attack plot.