The British jihadi bride whose four-year-old son recently appeared in an ISIS execution video was once a devout Christian who loved going to church, her father has said.

In an interview with The Sun, Sunday Dare, father of 25-year-old Grace, who now goes by the name Khadijah, said: "She was religious. She would read her Bible and pray all the time.

"We called her Grace after Amazing Grace the hymn.

"She went to church every week without fail, often three times. She was always smiling and singing at church, sat in the pews with all the grown-ups."

Khadijah, from Lewisham in southeast London, converted to Islam in 2010 and is believed to have been radicalised online. She fled to Syria in 2012 with her son, Isa.

There, she married Swedish ISIS militant Abu Bakr, who is since believed to have been killed. Khadijah has said on social media that she wants to be the first British woman to kill an ISIS hostage.

Isa appeared in a 10-minute ISIS propaganda video released by the militant group last week. It was titled 'A Message to David Cameron', and showed five hostages being killed.

Now dubbed 'Jihadi Junior', Isa said in the video: "We will kill the kuffars [non-believers] over there".

Sunday accused Islamic State of using his grandson as a "shield".

He told Channel 4: "He's my grandson. I can't disown him. I know him very well. He's propaganda. They are just using a small boy. They are just using him as a shield."