Everything is done at break-neck speed. If you’re 40 and living and working in London, you’re most likely either heading up a department at work or running the whole thing. “I still feel in my head that I’m 25, but I’m responsible for millions of pounds of budgetary spend, and while I used to be the last one standing at work drinks, now I can feel all the 20-year-olds waiting for me to leave before they can have fun” one 43-year-old friend, who heads up an advertising agency, says.