Never mind your legs; how’s your head? Sometimes it seems that the marathon is just as hard on the mind as on the body.

Training is fine because you can focus on the job in hand. But then the taper comes – and suddenly your mind is struck by weapons-grade maranoia, full of doubts, worries and the irrational urge to throw in one extra 20-mile long run ‘just to be sure’.

That’s even before the race itself, when your grey matter has to stop your body from charging off in mile one, and then has to kick-start your body when it falters at mile 20, the dreaded Wall.

Mental preparation is just as important as physical fitness on marathon day. There’ll be super-fit, well-trained athletes who go mad at the start or crack at mile 20, just as competitors of more modest ambitions will overcome the psychological challenge and…