More worryingly, another friend, Lauren, whose husband has run a dozen marathons including London, Berlin and New York, has warned Pam to “expect vomiting at the end” and that I “might look a bit green”. But in my mind, I hope to run an elegant marathon. Ideally, I would take it at a steady clip of 10 minutes a mile to finish in 4 hours 30 minutes, completing the second half in roughly the same time as the first. The reality is likely to be the opposite — that I kick off too fast and end up being passed and humiliated by runners in fancy-dress banana costumes as I grimace through the pain and limp the last six miles.