Until last week, I thought I had a good basic understanding of Theology of the Body, St John Paul II’s teaching on human sexuality. But ten minutes into last week’s London symposium, I realised I knew practically nothing. Studying the subject, you realise how deep it is – but you can also feel as though your head is about to explode.

Yet one of John Paul’s central insights is a simple one: that the deepest desire of the human heart is to be loved. One speaker, Sr John Mary of the Sisters of Life, poignantly illustrated this with the story of a Catholic soldier killed in Afghanistan. The soldier was shot through the neck, just above his bulletproof vest; as he lay dying in the arms of his commanding officer, he uttered his last words: “Tell me I’m loved.”