Breathalysers for every car?

Sarah Coles
Brethalyser
Brethalyser

John Giles/PA Wire/Press Association Images

The government's former chief drugs adviser, Professor David Nutt, has said that there should be an alcohol sensor in every car, so that it couldn't be driven by someone who failed a breath test.

He says it would dramatically cut the number of road deaths and injuries. But would it work?