Dogged historians are continuing to try and find the British director’s lost first feature, writes Geoffrey Macnab, and its proven to be a mystery every bit as compelling as his later films

As Ruben Östlund’s biting satirical comedy, ‘Triangle of Sadness’, about obnoxious billionaires on an ocean cruise becomes a huge hit at Cannes, Geoffrey Macnab looks back at films about the uber-rich and says it’s a topic filmmakers return to again and again in times of inflation and soaring bills