Tough new rules for skyscrapers have been drawn up for the City of London amid concerns its dense network of high-rise buildings are creating downdrafts and wind tunnels strong enough to knock pedestrians off their feet and cyclists off their bikes.
Under the scheme rolled out by the City of London Corporation developers will have to show how planned new towers will affect the street-level urban environment - including computer simulations of wind effects.
And stricter rules will mean average air speeds of more than eight metres per second (18mph) are considered 'uncomfortable'.
Such speeds will force architects back to the drawing board if that can be shown to potentially affect cyclists and pedestrians.
The Corporation's new plan is believed to be the UK's first framework which takes into account the impact on wind when planning applications for tall buildings are assessed.
The dense forest of skycrapers in the centre of London may create wind tunnels and currents strong enough to affect cyclists and pedestrians
It comes as a growing forest of tall buildings dominate the London skyline, with many in the Square Mile.
In recent years the Leadenhall Building (known locally as the 'Cheesegrater'), and the 'Walkie-Talkie' at 20 Fenchurch Street have been completed.
A further 13 skyscrapers of between 78m to 305m are either under consutruction or have received planning consent.
Alastair Moss, who chairs the City of London Corporation's planning and transportation committee, said: 'With the number of tall buildings in the Square Mile growing, it is important that the knock-on effects of new developments on wind at street level are properly considered.
'These guidelines mark another significant step that the City Corporation is taking to put cyclists and pedestrians at the heart of planning in the Square Mile, prioritising their safety and experience.'
Representatives of cycling groups said tall buildings created risks of 'walls of wind'
Roger Geffen, policy director at charity Cycling UK, said: 'Anywhere there are tall buildings going up, there is increased risk of encountering walls of wind as you ride.
'It makes cycling more of a struggle, but can also increase the risk of cyclists being suddenly blown off course, making their movements more difficult to judge for other road users.
'It's great that the City of London is considering how to minimise these risks in the design and siting of tall buildings in the future. Cycling UK would urge other city authorities to follow suit.'
In May, City of London Corporation approved the introduction of a 15 mph speed limit to reduce the likelihood and severity of road collisions, although the measure cannot be implemented without the approval of the Government.