A SPEED limit of 20mph on roads in residential areas across Scotland would prevent nearly 1,000 injuries a year and save the National Health Service at least £56 million, according to a new expert analysis.

Reducing the default speed limit would result in 15 per cent fewer casualties, avoiding seven deaths, 123 serious injuries and 812 minor casualties annually. It would only cost about £5m to make the change, campaigners say.

Scottish ministers are under mounting pressure to make 20mph limit the norm in towns and cities, with 30mph limits the exception rather than the rule. Scottish Green MSPs are planning to introduce a bill at Holyrood.

Some local authorities, such as Edinburgh, Fife and West Dunbartonshire, are already committed to widespread 20mph limits. But others, such as Falkirk and North Ayrshire, have no plans for permanent zones.

Using conservative assumptions and based on experience elsewhere, the campaign group 20’s Plenty for Us has calculated the health and economic benefits of the lower limit in Scotland’s built-up areas. They conclude that it would result in 942 fewer injuries every year.

That would save the NHS £14m trying to treat those that die, £26m treating serious injuries and £16m dealing with minor injuries. The overall annual savings for the NHS in Scotland would be a minimum of £56m, the group says.

That compares to an estimated cost of £5m for the signs needed to introduce blanket 20mph zones, they say.

The new analysis follows a detailed study by the NHS in Wales examining the impact of replacing 30mph with 20mph limits. It concluded that six to10 lives would be saved and 1,200-2,000 casualties avoided every year, saving the NHS between £58m and £94m annually.

“20mph limits bring massive public health economic savings,” said 20’s Plenty’s campaign manager Anna Semlyen. “Retaining 30mph is unethical when we know that so much risk and harm can be easily prevented. Politicians must vote for default 20mph limits.”

The Scottish Greens argued that there was “no logical reason” for retaining 30mph limits in built-up areas. “The time for a national switch has arrived, building on the progress made already in council areas such as Edinburgh and Fife,” said Green MSP and environment spokesperson, Mark Ruskell.

Living Streets Scotland, which represents pedestrians, called on the NHS in Scotland to press local authorities for 20mph zones.

The Scottish Government is keen to encourage councils to introduce 20mph zones but has no current plans for a nationwide scheme. A spokesman for the Government body Transport Scotland said: “We believe decisions on urban speed limits are best taken at local authority level so there are no current plans to lower 30mph limit to 20mph on a national basis."