An “extremist” mother-of-six who took pictures of her toddler son holding a toy gun and daydreamed about sending his eight-year-old brother to fight jihad when he grows up has been jailed for five years and three months for promoting terrorism on social media.

Runa Khan revealed her views on Facebook, encouraging Muslim women to urge male relatives to fight and posting a picture of a suicide vest. She also praised an article giving tips on how to prepare young children for jihad and unwittingly passed a route to Syria to an undercover police officer.

Khan appeared to glorify the murder of Lee Rigby, while she repeatedly spoke of her desperation to travel to Syria in messages on WhatsApp.

When she was arrested police found a photo of her two-year-old son with a toy assault rifle and a jihadi book on her phone, as well as images of her and her older children holding a sword, Kingston crown court heard.

The 35-year-old, from Luton, admitted four charges of disseminating terrorist publications between July and September 2013. In one Facebook post Khan described how when she was getting her eight-year-old son ready to go outside to play, she pictured handing him a rifle in the future and sending him out to “play the big boy’s game”. Khan suggested in messages to a man fighting in Syria that she was planning to “come with my little boy”, the court heard.

Sentencing Khan, Judge Peter Birts QC described her as an avowed fundamentalist Islamist holding radical and extreme beliefs. He said: “You hold to an ideology which espouses jihad as an essential part of the Islamist obligation.

“I sentence you not for your beliefs, abhorrent though they are to all civilised people, but for your actions in disseminating terrorist material with the clear intention of radicalising others.”

Referring to her online activities, he said: “Your purpose was to encourage and promote your particular brand of violent fundamentalism. “You were deeply committed to radicalising others, including very young children, into violent jihadi extremism.”

The judge added: “You appear to have no insight into the effect of radicalising your children, having selfishly placed your own ideology and beliefs above their welfare in your priorities.”

Paul Jarvis, prosecuting, said Khan’s online activities revealed her “extreme Islamist views” and her desire to travel to Syria.

Between April and October last year Khan exchanged messages on WhatsApp with Mohammed Nahin Ahmed, who was jailed after he admitted fighting in Syria alongside an al Qaida-linked terrorist group.

During their discussions Khan asked Ahmed about the possibility that he might be able to find her a husband from among the ranks of those fighting jihad, Jarvis said.

In September last year she wrote: “Trying to clear debt n join u … I’m gonna come with my little boy.”

Khan used a Facebook account in the name of Khawla Khattab but her activities on the site were revealed after she passed the details of a route to Syria sent to her by Ahmed to an undercover officer, which formed the basis of one charge against her.

The investigator gained access to the Facebook posts that were only visible to Khan’s 241 friends and the three remaining counts were based on material she posted.

On 30 July she posted an image of a suicide vest emblazoned with the words “sacrificing your life to benefit Islam”.

In September she shared an article written by another user, which set out a detailed blueprint for “Raising Mujahid Children”. Khan said: “Sisters this is excellent.” The document included suggestions that even very young children should be trained for jihad, the court heard.

On the day after Lee Rigby was murdered near Woolwich Barracks in May last year, she changed her profile picture to an image of what appeared to be a soldier carrying a dead or injured comrade with the caption Hell For Heroes.

She also shared a post by another user which complained about Muslims who condemned the killing.

Police raided her home on 16 October last year and seized her iPhone. It contained several photographs including a picture of Khan’s two-year-old son wearing a turban and holding a toy assault rifle, a picture of him holding a copy of a Jihadi book, pictures of her nine-year-old and teenage sons holding a sword and pictures of Khan holding a toy assault rifle and brandishing a sword.

When she was arrested, Khan told police she was only interested in going to Syria for humanitarian purposes.

She denied there was anything sinister about the photographs on her iPhone. Khan denied being any threat to the UK and insisted she disapproved of the murder of Lee Rigby.

When an officer suggested to her that she must have known her Facebook activities would encourage others to join violent jihadi activities, she replied: “It’s because of the Qur’an, isn’t it? This is what the Qur’an says, please read the Qur’an. I’ll see you next time in a turban and a big beard.”

Khan, who appeared in the dock wearing a niqab with only her eyes visible, was given a police caution in July for assault. When she was arrested over that incident, the court heard she told police: “I will blow you up.”

Jo Sidhu QC said in mitigation that Khan was obsessed with the situation in Syria but did not advocate a global jihad.

He said she recognises that what she has done offends English law and makes no excuse for her behaviour.

Sidhu said she has “inflexible religious sensibilities”, adding: “We are dealing with someone whose thinking is deeply immature.”

In an interview with the BBC’s Newsnight Khan said: “I was posting up my beliefs.”

Asked if there was anything she regretted, she said: “We’ve moved on, haven’t we. I’m 35 now. So I can’t look back. If I kept looking back into my past life, I’d never be able to move forward. My kids are going to have a normal life, in fact they are going to have a better life, you know because I’m not around my sister is going to cut down on her work hours, she is going to spend time with them, my mum is going to spend more time with them.

“If we could we wouldn’t live in Britain. My passport has been taken away from me, Britain is the last place I would want to live in and I’m sure that you know the majority of people with my mindset are actually behind bars because they don’t want to stay in Britain.”

She said she does not know how many women there are like her. “But as far as I’m concerned all the Muslim women, all the women should be how I am.”

She said that when she talks about jihad she does not mean killing innocent people, but people who are a threat to her religion.

She added: “I have always said I don’t believe in going and blowing myself up in a shopping centre where there are going to be innocent children. And when I spoke about suicide missions, I only spoke about it because it’s a much-feared war tactic, which should only be used in a battlefield, not anywhere else.”