Getting girls back to school was one of the top priorities for international donors and the Afghan government after the collapse of the Taliban in 2001. At that time, of the one million children in school, it is estimated that only 5,000 were girls.

Now, thanks to considerable efforts, girls' education is considered one of Afghanistan's few success stories. Of the 6.7 million pupils enrolled in school in 2010, 2.5 million were girls, according to the Afghan Ministry of Education.

However, more than half of all girls still do not attend school and barriers remain.

A problem is the lack of female teachers. Many families will not allow their daughters to attend school after they hit puberty if their teacher is male. Indeed, enrolment figures for girls fall at middle and high school levels.

Many husbands will not allow young wives to continue their education after their wedding. A 2011 report found that 17.3 per cent of girls aged 15-19 were married.

The deteriorating security situation also plays a significant part.

In 2008, there were 670 attacks on schools, including arson and the murder of teachers and students.

The Taliban is trying to show a softened stance in anticipation of inclusion in the Afghan government, as part of a negotiated peace settlement, ahead of the Nato pull-out in 2014. It claims it was not against girls attending school; just mixed schools.

But human rights advocates are concerned that if the group regains even a slice of power, girls' education will be one of the first things to be compromised.