Spirituality Makes Tony Blairs Sister-in-Law Convert to Islam TEHRAN (FNA)- Former British Prime Minister Tony Blairs sister-in-law Lauren Booth said she converted to Islam after she felt the deep spiritual touch of Islam during her recent visit to the Shiite Shrine in the holy city of Qom in Iran. My experience shows that Islam is the religion of love and kindness towards friends and even enemies, Islam wants us to have the best spirits ,Booth told FNA. I converted to Islam in London a week after (the visit to Qom) she announced. Blairs sister-in-law revealed over the weekend that she has converted to Islam. Booth, who is half-sister to Cherie Blair and a Catholic by birth, switched faith after a recent visit to Iran. A human rights campaigner and journalist, she works for Press TV, Irans English language international news channel.