As Louise Haigh waited behind the Speaker’s chair before her first Prime Minister’s Questions she chatted with the chancellor, John Healey, smiling and laughing in the way people do when they know lots of people are looking at them. At the despatch box the Welsh Office minister Anna McMorrin had the unenviable pre-PMQs task of trying to answer questions to which almost no-one in the rapidly filling house paid any attention, like a teacher trying to set homework after the bell has gone.