Emily Knight lives with five housemates. One of them is her partner. But this isn't a student house-share. They are all in their 30s, have no plans to break up the group, and Emily can't imagine life without them all. So could the rest of her life be built on these friendships? Traditionally life's big chapters - housebuying, raising kids, retiring - are seen as things you probably do with a romantic partner. In BFFs, Emily meets people from across the UK doing things differently, and asks if a life built on friendship can really work. In Greater Manchester she meets Sam and Sean, renovating the three-bedroom house they bought together last year. Sandra and Lisa reflect on raising their daughters as two single mums together in Hull. In Colchester, Andy, Anne and Barbara are three members of a bigger group of friends living in a co-housing settlement. For them, friendship is a way of guarding against loneliness as they get older. And from the United States, Emily hears about the developing concept of "platonic co-parenting", while writer Rhaina Cohen explains why she feels deep friendships can be unappreciated and misunderstood.

Producers: Paul Martin & Emily Knight A BBC Audio Wales Production for Radio 4