Leading British lawyer and committed Catholic Cherie Blair investigates Christianity over the last 100 years and explores its future prospects. She examines the challenges to Christianity posed by the trauma of war and political oppression in the 20th century, which culminated in the genocide of the Jews in the Holocaust. Into the huge God-shaped hole fell the modern 'faiths' of materialism and secularism. Christianity was becoming and more isolated by so-called 'progress', and this marginalisation was exacerbated by the new hedonistic anything-goes society of the 1960s. But there is one part of the Western World where Christianity has bucked the downward trend and has never been stronger - the USA. Cherie uncovers the reasons for its continued success there and looks at what the future holds for Christianity. Are we living in a post-Christian age? Or is the 21st Century really going to be the Christian century?

• Michael Portillo
• Cherie Blair