A new Channel 4 documentary, broadcast on Thursday 10th August at 9pm, will uncover the volatile relationship between Princess Diana and her remarkable stepmother - from early clashes to late reconciliation. Featuring exclusive interviews from friends and insiders, and fresh insights into Diana's early years this is a tale of two formidable women that follows their lives through marriage, divorce and tragedy to eventual friendship.

Raine Spencer was a force of nature. With the help of her larger-than-life mother, the romantic novelist Barbara Cartland, she rose from relatively humble origins to become a Countess three times over and a member of the royal family.

A former 'Debutante of the Year', Raine became at the age of 23 a canny and pioneering politician and campaigned successfully to save many London landmarks from destruction, before becoming stepmother to the future Princess of Wales. She proved a divisive figure within the family - doted on by Diana's father Johnnie Spencer, but loathed by Diana and her siblings.

Raine attracted controversy by making sweeping changes to Althorp, the Spencer family's ancestral home. She scandalised purists with her no-nonsense attitude towards making money: selling off the Spencer family assets. But when Diana’s marriage unravelled, Raine's relationship with her was transformed. The pair forged an unlikely alliance and Raine went from so-called 'wicked stepmother' to becoming one of Diana's closest confidantes.

Prod co: Firecrest Films

Prod/Dir: Stephen Finnigan; Exec Prod: Iain Scollay