The young boy in the new Islamic State execution video is the son Grace Dare, a female British Islamist who has links to the killers of soldier Lee Rigby.
The child, who is shown wearing camouflage and a black headscarf, is Isa Dare, whose mother converted to Islam and then fled to Islamic State to become a jihadi bride.
Grace Dare, who changed her name to Khadija after converting, grew up in a Christian family of Nigerian descent. She started attending the Lewisham Islamic Centre, however, and grew increasingly radical in her Islamic beliefs.
Michael Adebolajo and Michael Adebowale, who murdered soldier Lee Rigby on the streets of London, are also believed to have worshipped there, although the mosque denies this.
Grace’s father, Henry Dare, confirmed to the Telegraph that the child in the video, who has been dubbed “Jihadi Junior”, is indeed his grandson Isa.
Last year, Grace boasted about her son on social media, posting of Isa holding an AK-47 rifle that he seemed only just big enough to lift.
Speaking last year, her mother, Victoria, said: “I still call her our Grace.
“I want her back in my life. She is the only child that I have and the devil took her away.”
She has been in Syria since 2012 and married a man of Swedish origin called Abu Bakr when she got there. He is thought to have since been killed.
Grace has previously used social media to gloat about the beheading of American hostage James Foley and has said she wants to be the first woman to kill a hostage.
Speaking to the Telegraph, a former neighbour of the Dare family said: “I got to know the family very well because they lived downstairs to me. The parents were very devout Christians from Nigeria. Grace was a lovely, sweet child with a very warm smile.
“She used to take my dogs out for a walk and I would give her a pound. She was an extremely bright child who was streets ahead of other children her age.
“She moved away when her parents split up, but I would still see her around occasionally. Around five years ago my partner was in Deptford market and she heard someone calling her name. When she looked round she saw this girl in a full Burkha and she said ‘It’s me, Gracie’.
“She said she had converted to Islam and seemed very proud about it. I was very shocked when I heard she had gone to Syria, it was not something I could have ever imagined knowing her when she was growing up.”