MOTORISTS in Scotland face driving on crumbling surfaces in the years ahead, according to a report that highlights “major concerns” about the integrity of the country’s road network.

Public spending watchdog Audit Scotland found that a more than one-quarter of the motorway network was defective in 2014/15, compared to one-fifth in 2011/12.

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The condition of local roads has remained generally steady, with 63 per cent considered to be in an acceptable condition, but in the worst-performing area – Argyll and Bute – only 44 per cent of roads were acceptable.

The report warned that both councils and Transport Scotland are underspending on roads maintenance by tens of millions of pounds a year and drivers will face worsening conditions in future unless action is taken.

It estimated that poor and defective roads have already played a part in six fatal and 64 serious crashes since 2010 and that the increasing reliance of cheaper “surface dressing” repairs to fill in cracks and potholes could end up costing the public purse more in the long run.

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It comes days after analysis by RAC revealed that pothole-related breakdowns are higher in Scotland than anywhere else in the UK.

Douglas Sinclair, chairman of the Accounts Commission, said: “The state of our roads is a major concern for the public. Surveys show that they remain dissatisfied, despite these concerns being flagged up in our two previous reports. Their voice needs to be listened to.”

The report found that Transport Scotland spent £24 million less on structural maintenance in 2014/15 “than it considers necessary to keep trunk road condition at its current levels”.

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Audit Scotland also noted that two and a half times as much is spent on trunk roads and motorways in England, where only four per cent were identified as potentially in need of repairs last year compared to 13 per cent in Scotland.

Meanwhile, roads in Glasgow, Edinburgh and Dundee were among those deteriorating, but the Western Isles and East Renfrewshire notched up the biggest improvement.

Audit Scotland said council budget reductions have tended to focus on areas such as roads and transport in the face of spiralling social care costs and the need to maintain teacher numbers.

The report warned that “the continued prioritisation given to services such as social work and education”, combined with looming cuts to local government funding could put the roads maintenance budget “under further pressure”.

Andy Willox, the Federation of Small Businesses' Scottish policy convenor, said: “The vast majority of Scotland’s smaller businesses rely on cars or vans. Every plumber, pizzeria and pipe-fitter can tell you how our run-down local roads hurt their business.

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“We need to see our political leaders develop a plan to fix this problem and many in the business community are fed up with a lack of action.”

Scottish Conservative transport spokesman Alex Johnstone said: “This is a damning report which exposes how the SNP has let the state of Scotland’s roads slip significantly.

“It’s incredible to think that in some parts of Scotland there are more bad roads than good.”

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Neil Bibby, Scottish Labour transport spokesman, added: “Rather than give local councils the resources they need to maintain the condition of our roads the SNP have instead chosen to cut over £1 billion from local authorities since 2011.”

Stephen Hagan, of council umbrella body Cosla, rejected the suggestion that councils were not prioritising roads.

He added: “The truth of the matter is that local government faces huge challenges on maintaining or improving road quality, but there are no easy solutions.”

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A spokeswoman for Transport Scotland said it had invested £6.5 billion in trunk roads since 2007 and delivered improvements to 235 miles of carriageway in the last year.

She added: “It is the responsibility of each local authority to allocate resources on the basis of local needs and priorities.”