What exactly does true friendship mean in the modern world?

Kate Leaver is the author of The Friendship Cure: A Manifesto for Reconnecting in the Modern World, which may have the answers.

Kate defines friendship as being able to "share confidences with one another, when the relationship is based on loyalty and you exchange a level of candour and support in a crisis."

Friendship has long been associated with positive or negative mental health, but studies have shown that it can actually affect our physical health too. In fact, as Kate says, "Loneliness and social isolation is as dangerous as smoking 15 cigarettes a day."

Friends are often described as the family we choose, so why is it that so many of us drift from people we once considered close friends?

Kate points to an Oxford University study that has shown we lose two friendships each time we enter a serious romantic relationship: "We're allowing good people to drift out of our lives purely because we don't prioritise friendship."

But can you actually have too many friends, or is it more about quality than quantity? And how do you know when you've got a really good one?

"If you can count on one hand the type of people who lift you up and make your life better every day, who make you a better person and who you can count on in times of crises, then you're an incredibly lucky person."