I  wrote Symphony with Ammar Malik, Steve Mac and Jack Patterson from Clean Bandit. To start with, it sort of had a negative meaning: Ammar and Steve had an idea about ‘music sounds better without you’. It’s very hard to make negative songs.

There are a few that really work, like Beyoncé’s Irreplaceable – that’s one of my favourite records in the world. It has to be so clear, and it needs to find joy in the heartbreak.

The first ...