Drink-driving bans and fines should be reduced if the government lowers the legal alcohol limit, a road safety charity has suggested.

Justice Secretary Kenny MacAskill has said proposals to cut the limit from 80mg of alcohol per 100ml of blood to 50mg will be brought forward later this year, with a view to the change taking effect as soon as possible.

The Institute of Advanced Motorists (IAM) said the government should take into account the impact a driving ban and other sanctions would have on people's lives before seeking to punish them for driving after a single glass of wine.

IAM director of policy Neil Greig also said enforcing bans for lower limit drivers could divert police resources from more serious offenders.

He told The Herald: "Should a driver who is stopped after taking one glass of wine and who has not caused any problem on the road face a 12-month ban, a very large fine, loss of job, seven years of huge insurance premiums and even the possibility of forfeiture of their car?

"This is not an easy question to answer but the IAM believes it must be addressed by the legislators and the enforcement agencies.

"In many parts of Europe a lower limit has been introduced with a lower fine and shorter bans to address this very point."

He added: "If the number of drivers who would be caught by the lower limit is high, this would have major implications for police resources and could divert attention away from the worst offenders who currently ignore the limit but who actually cause most of the worst crashes."

Drink-drivers currently risk a 12-month driving ban, six months imprisonment, a £5000 fine, the loss of their car and a criminal record.

A Scottish Government spokesman said it is for the procurator fiscal to decide whether it is in the public interest to prosecute and to decide on the appropriate sentence or penalty.

He said: "The Scottish Government has long called for a reduction in the drink-driving limit to 50mg which would bring Scotland into line with the rest of Europe.

"We strongly believe that reducing the drink-driving limit will save lives."