Money for fixing local roads is now so 'inadequate' that one on every five routes has less than five years of structural life left - warns one of the most in-depth studies into the condition of our carriageways.

More than £3 billion, estimates the Asphalt Industry Alliance's annual report, is needed across the south east to fix the backlog of repairs while local authorities, including Kent County Council and Medway Council, would have needed an extra £10.7 million last year just to meet their own targets for road conditions.

The ALARM survey - described as the 'most authoritative and comprehensive study into local road maintenance funding' - makes for bleak reading and forecasts only worsening conditions and mounting costs that will continue to spell misery for road users.

While the cost of fixing the growing backlog of required repairs is estimated to be running into billions, the organisation suggests the mammoth amount of work required to bring roads up to standard would also take an average of 14 years to complete.

Rick Green, AIA chair said highways engineers can only do 'so much' with the resources they're given and while the spring budget acknowledged a problem, any share of the additional £200 million one-off lump sum will not be enough.

"It represents around 16% of the average shortfall in local authorities’ annual budgets in the south east and will do little to improve overall structural conditions and stem further decline" he explained.

"We all appreciate that there are difficult choices to make with demands and pressures on the public purse coming from every area, but not investing in local road maintenance only leads to worsening conditions, which impact on other locally provided public services, a rising bill to fix the problem and more road user complaints."

The equivalent of 500 potholes are filled in the south east each day but roads are only resurfaced, on average, less than once every 117 years, explains the study.

Nicholas Lyes, Head of Roads Policy at the RAC, added: “These findings make for terrible reading and will come as no surprise to anyone who is forced to endure our pothole-plagued roads on a daily basis. It’s incredible that council funding is now so inadequate that almost one-in-five roads have under five years’ structural life left.

"This means the gap between the money councils have and what they need is widening - with road users ultimately left suffering."

British Cycling is among those now joining the AIA in calling for local and rural roads to be given 'national priority for investment'.

Nick Chamberlin, Policy Manager at British Cycling, added: "“Local and rural roads need desperate attention. The government continues to kick the can down the road and now the repair bill is growing out of control.

"Potholes and poor road surfaces are a problem that all road users can unite on, but they are particularly dangerous for people who cycle. The problem demands a proper long term funding solution."