The policy, which came into effect yesterday, is being introduced after a sharp increase in the number of positive breath tests recorded in London.
Assistant Commissioner Paul Manning, responsible for traffic policy, said: "Although most people are responsible and don't drink and drive, there's still a hard core of motorists who flout the law and put innocent people's lives at risk. Our message is quite clear - if you have the slightest accident you are liable to be breath-tested."
A pilot scheme has been operating in south-east London since the beginning of the year. Officers will continue to exercise their discretion in cases where drivers are injured.
An extra 200 breathalyser kits have been issued to traffic garages and police stations throughout London to put the new policy into practice.
Similar policies have already been adopted by several other forces.
Mr Manning revealed that positive tests in the Metropolitan Police area rose from 8,840 in 1993 to 11,251 in 1994. In the first six months of this year there were 8,057 positive tests.
So far this year around 15 per cent of those asked to undergo tests had either failed, refused or been unable to provide one. That compares with 9 per cent last year and 8 per cent in 1993.
Mr Manning said the reasons for the rise were not entirely understood, but it was probable that it reflected both better targeting of offenders by police and changing drinking habits associated with the introduction of all day opening.Reuse content