A relationship with a brother or sister might well be the longest we ever have. It can be a source of huge mutual support in the sharing of great joys, and in the struggles of tough times. But sibling relationships can also be marked by conflict and rivalry, as we've seen in the public fracture of the relationship between Prince William and Prince Harry. Roy Jenkins meets people who’ve been estranged from their families for many years, and hears about the heartache family fracture can cause. Dr Lucy Blake, developmental psychologist at the University of the West of England, explains that in her research she’s found that family estrangement is more common than we might think, but also how our notions of an 'ideal' family are hard to live up to. Fern Schumer Chapman, author of ‘Brother, Sister, Strangers: Sibling Estrangement and the Road to Reconciliation’ examines the taboo around sibling estrangement. We examine how religious belief can be the cause painful disputes, and Assia shares how her conversion to Islam led to estrangement with her family. Amanda Morris from the Muslim Council of Britain explains the support offered to new Muslims, and how cherished sibling relationships are in the Qu’ran. We hear how faith can sometimes help heal divides, and Joe Connor from Elam Ministries explains how they help foster reconciliation between Christian converts and their families.