Sharon was working late one November night and the month was a grey and drizzly month in the year.

Everyone else had gone home but she had to finish some research on a new investment programme they were working out for a big pension fund.

She stopped to massage her eyes, Chinese fashion, her elbow on the desk and her palms pressed into her eyes, shutting out light and easing the strain on the iris, at the same time, letting her mind go blank. When she was very tired, this often helped to ...