Those caught driving over the new limit would be subject to a “two strikes and you’re out” rule under which they would receive six penalty points for the first offence and only be disqualified from driving if they reoffended within five years.
Road safety groups fear that abolishing the automatic ban will send a confusing message to motorists and encourage some to risk drinking and driving because the consequences of being caught would be less serious than they are now.
The Times disclosed last year that ministers were planning to lower the limit to 50milligrams of alcohol per 100millilitres of blood, from the existing limit of 80mg.
Research by University College London found that lowering the limit would save 65 lives and 230 injuries a year. It would also save the economy £119 million a year by reducing medical costs and lost working time resulting from accidents.
But the Government is concerned that, if it maintains the automatic 12-month driving ban for breaching the lower limit, thousands more drivers could lose their licences and therefore risk losing their jobs.
Some drivers, depending on their size and metabolism, would breach the 50mg limit after just one drink. Under the 80mg limit, almost everyone is legally fit to drive after one drink even though studies have shown their driving ability would be impaired.
Under the proposal, the automatic ban for breaching the 80mg level would be maintained but offenders having alcohol levels between 50mg and 80mg would be penalised only with points on their licences and a fine, or possibly be instructed to attend an alcohol awareness course.
A consultation paper due to be published within weeks will offer a number of options and will invite comments on the impact of removing the automatic ban.
In 2006, 540 people were killed in drink-drive crashes, up from a low of 460 in 1999. About 95,000 drivers a year are banned for at least 12 months for failing a breath test or refusing to be tested.
Britain has the highest drink-drive limit of any large European country. Most countries have adopted 50mg and some, including Poland and Sweden, have a 20mg limit.
In most countries, drivers found to be slightly over the limit are either fined or banned from driving for short periods. In France, drivers caught between 50mg and 80mg are fined and given six penalty points.
Two thirds of AA members favour a reduction in the alcohol limit, according to a survey published today.
Women were more likely to support a lower limit, with 75 per cent in favour compared with 62 per cent of men, according to the Populus survey of 17,500 AA members.
Cathy Keeler, head of campaigns at Brake, the road safety charity, said: “We will save the most lives by reducing the limit and keeping the automatic ban. We must not distort the simple message that being caught over the limit results in disqualification.”
The influential Parliamentary Advisory Council for Transport Safety said it was undecided about whether to support the ending of the automatic ban.
Rob Gifford, the council’s director, said: “If it resulted in double the number of people losing their licences for breaching the lower limit, it could clog up the courts and create more of a problem because people would just drive while disqualified.”
In another tightening of the drink-drive law, motorists caught well over the limit will have to resit their driving test after serving their ban. The Government is also considering giving police the power to stop drivers at random and breath test them. At present, police can only stop a driver if they have reason to believe that an offence has been committed.
Drivers are less likely to be breath-tested in Britain than in most other European countries. A study in 2004 found that only 9 per cent of drivers in Britain had been tested in the previous three years, compared with 64 per cent in Finland, 41 per cent in Sweden and 32 per cent in France. The EU average was 29 per cent.