In the frescoed ballroom of the International Butler Academy (TIBA) in the Netherlands, a gaggle of students shuffled into line. “You may have walked in a certain way for 25 years, but this is not how you do it as a butler,” said their etiquette instructor, addressed by everyone as Mr Munro. He ordered them to slot their arms behind wooden crosses, which they held against their spines – “torture devices” to correct posture. “Now relax!”