Throughout our history people, usually young people, have left these shores to fight for something they believe in, usually but not always, such actions were miles away and did not directly impinge on, or threaten this country. Many returned in coffins or body-bags and never got to reflect on the error of their ways. Isis was a different thing altogether it had a murderous edge to its beliefs and was perceived at least to have little sympathy with or for its enemies.
This young women was a school girl when she left and is still only 19 now, she has borne children and has lost children and her husband, the public perception is that she seems unmoved by all that has happened to her and as far as we know, nothing is known about any crimes she herself may have participated in.
Since she lost her passport and right to enter this country she has no rights whatsoever in the UK. Anything she may be offered or subsequently be given by the State will be at the discretion of HM government.
Young people do silly things, stupid and sometimes evil things. If it is judged that this girl no longer presents a threat to the people of this country then perhaps she should be allowed to come back and at least state her case. If she does not renounce her past, to show she wants to make a new start, then imprisonment is all that she can hope for, she would need to make a public act of atonement that would leave no one in doubt of her sincerity and wish to make amends for what she did, either by supporting Isis or taking part in its activities.
There is a danger that she maybe seen as a 'Isis martyr' rather than an 'Isis stooge' in some quarters, and the Government needs to take advice on this particular aspect before any permissions are given.