Young girls indoctrinated by the Islamic State can be married off at the age of nine and are taught in schools to be good wives and mothers. The young children, referred to as 'Pearls of the Caliphate', are also subjected to a regime of systematic rape and abuse, a report has shown.

A study by the London-based thinktank the Quilliam foundation, 'The Children of the Islamic State,' has documented in detail the Isis blueprint for girls and women inside its territory.

"It is considered legitimate for a girl to be married at the age of nine, or at the latest by 16 or 17," the report stipulated. Under the jihadi group's harsh regime, they are also only expected only to leave the house in exceptional circumstances. "They are to be fully veiled, remain hidden, and never leave the house," the study explains.

'The Children of the Islamic State' outlines a world in which girls are given a domestic education whereby they are taught to look after the needs of their husbands, bring up their children with IS (Daesh) ideology, and maintain their house. They are taught to be proficient in skills like sewing and knitting.

The study quotes Isis propaganda which claims the woman's role is "building the Ummah [community], producing men, and sending them out to the fierceness of battle".

The Quilliam Foundation also reported on the brutality experience by girls under Islamic State rule. Some of those who had first-hand knowledge of the widespread rape and abuse said some of the girls were probably too young to understand what was happening to them. Several women reported that, while in captivity, young women and girls were taken and raped on a daily basis by IS fighters. An elderly woman reported that the young women would come back after some hours or days in a "miserable condition".

One described how she was raped in Mosul and heard the screams of girls also being absued in an adjacent room. She recounted how she saw an IS fighter threaten one young girl at gunpoint who had been resisting. After Mosul, they were taken to a school in Tal Afar where there were reportedly more than 100 small children.

The town in north-west Iraq appears to have been centre for the abuse of women and small children after it fell to the Islamic State in June 2014.

The second girl said she was raped in a hall where she was being detained with other women. Guards raped her three times a day for three days, according to her account. She also saw an eight or nine-year old girl being raped openly in the hall.

The study has been endorsed by the UN and is due to be published in Parliament on Wednesday (9 March). Its says 50 British children are growing up in the Islamic State, with an estimated 30,000 foreign recruits, more than 800 of them from the UK fighting for Daesh.

There are currently 31,000 pregnant women in Islamic State, according to the research. Noman Benotman, President of Quilliam, said in a statement: "This is one of the gravest situations on earth. Children are the key to the future. Indoctrination in Islamic State begins at birth, and increases in schools and training camps. Children are instructed in a particular interpretation of shari'a, desensitised to violence, and learn specific skills to take up the banner of jihad."