How late is it acceptable to arrive at a social event? Fifteen minutes? Twenty? Half an hour? Does there come a point when it is just too late to turn up at all? I confess to not being particularly consistent at timekeeping. I was mindful of this in mid-January when I was invited to a very special event at Spencer House: a recital by a string quartet from the London Symphony Orchestra. I am not known for my love of classical music, but two things appealed. First, the recital was to last a mere 35 minutes, leaving plenty of time to chat to the select group of attendees and to admire the 18th-century mansion. Second, I was invited by a senior banker in the City of London whose company I enjoy very much. Thus it was that I readily responded, and resolved to be on time.

I have been brought up to attend functions that I have accepted, and not to cry off when I am later offered the opportunity to do something else. So when I was subsequently invited to the launch of Sarah Brown’s book, Behind the Black Door, on the same night, Tuesday March 1, I felt I had to decline. The string quartet was calling, and anyway it would have been bad manners.

Even so, I was particularly disappointed not to attend Sarah’s book launch, and not just because I missed meeting Jimmy Carr. It was also because Sarah has made regular appearances in this column as PLG, my Pilates Loving Girlfriend. When an advance copy of the book arrived at my office on the afternoon of the launch I was so busy working my way through it that I nearly made myself late for my Spencer House appointment. I was completely absorbed in scouring its 435 pages (and 12 pages of acknowledgments) seeking mentions of the hours and hours of Pilates that she has made me endure. My stance on Pilates, as regular readers know, is very clear. I do not consider it a real exercise, and anyway I do not need to strengthen my pelvic floor as I have had three caesarean sections.