For the serious running enthusiast, knowing what clothes to buy can be a bit of a daunting prospect.

Running shoes are getting ever-more sophisticated - and expensive - but that's just the start of it. A decent shirt with UV protection, sweat-activated technology and so on can set you back upwards of £50, while selecting the best running shorts can involve an unsatisfactory trade-off between comfort and practicality.

None of these concerns seemed to have bothered Boris Johnson, who was photographed in this stunning get-up while out jogging on Tuesday.