grace dare , who now uses the name khadijah , is with isis in syria .
her heartbroken mother victoria , from lewisham , has spoken for first time .
has issued a plea for her daughter and grandson to come home .
says dare was a devout christian as a child and ` loved to pray '
her daughter has become a terrorist poster girl and regularly issues threats .
dare has said she wants to become the first woman to behead a westerner .
her swedish husband abu bakr has reportedly been killed .
britain 's jihadi brides , tonight at 9 pm on bbc2 .