London councils did not consider the economic cost of implementing 20mph speed limits across the capital, The Telegraph can reveal.
Eleven boroughs in the capital have blanket 20mph speed limits across all of their roads, a move made in the hope of reducing the number of deaths and serious injuries among pedestrians and cyclists.
Transport for London (TfL) says that every year 1,000 people are injured or killed by drivers exceeding the speed limit.
