Walk all 72 steps and, the poster reveals, you will burn a total of 18.2 calories – which works out at just under 1% of the recommended daily intake for an average woman (and a bit less than that for the average man).

But as Mayor of London Boris Johnson says: “Anything that gets people more active and helps tackle obesity is a good thing in my book.”

Johnson was commenting on the launch of StepJockey, the company behind the poster campaign. StepJockey is the brainchild of Helen Nuki, co-founder of the behaviour change research agency Monkey See. It has the backing not only of the Mayor of London, but the Department of Health too, having won a Small Business Research Initiative competition for innovations designed to curb obesity.

StepJockey works by encouraging participants to rate the stairs they use, whether at home, in the office or in public places. Once rated, posters can be bought or printed off for free and displayed next to the relevant staircase. QR codes on each poster and a free companion app allow individuals to keep track of how many calories they burn over time, just by taking the stairs.

Nuki said that behavioural economics was integral to the StepJockey concept in that it plays to many of the key principles. For instance, Nuki said, stair-climbing can be easily incorporated into everyday routines; it has salience, because the posters interrupt people’s habits at the point of behaviour; and it is a visible activity, so it plays to the herd effect.

Research to validate the idea found that the presence of StepJockey posters increased stair usage by up to 29%, while those most influenced were ‘overweight’ people (those with a body mass index of 25 and above).

Nuki said: “It’s exciting to be able to demonstrate not only that behavioural economics can impact research, but that it can also inspire original yet simple marketing and business ideas.”

• StepJockey is online here