More than half a million potholes were reported by members of the public to local authorities in Britain for repair in 2017, an increase of 44% on two years earlier, according to data obtained by the RAC.

A freedom of information request made to the 212 councils in England, Scotland and Wales responsible for roads revealed that 512,270 potholes were reported last year to 161 authorities compared to 356,432 from 152 councils in 2015.

But when extrapolating the numbers to take account of the likely reports from the authorities who were unable to provide the RAC with data, the total is probably nearer 674,229 in 2017. The 2015 equivalent is 508,651 which represents a smaller increase of 33%.

English authorities, not including London, saw the worst rise in the number of pothole reports between 2015 and 2017 with a 55% jump from 269,486 to 417,881. Wales experienced a lesser increase of 22% with reports going up from 9,519 to 11,638. However, when comparing last year with 2014 in Wales the difference was greater (40% increase) with only 8,287 potholes reported then.

In Scotland there was only a slight rise of 2% from 2015 to 2017 (55,961 to 56,859), but a 52% increase from 2014 with 37,432 reports. Taking London on its own, there were 25,892 potholes reported last year in contrast to 2015 when there were just 21,466, an uplift of 21%. From 2014 to 2017, however, there has been a 13% drop from 29,870 four years ago.

When looking at the inclusive four-year period from 2014 to 2017, a total of 1,737,161 potholes were reported across Britain but, factoring in those authorities that did not provide data, the figure is more likely to be well closer to 2.4m (2,429,422) over the four years, say the RAC.

RAC head of roads policy Nicholas Lyes said: “It is shocking to see the number of reported potholes in Britain has risen by nearly 50% in two years. Our own analysis of breakdown data shows the damage suffered by motorists is a constant source of frustration and expense, but the scale of the problem is obviously far greater than the numbers show.

“Perhaps motorists are more inclined to report pothole defects than they were a few years ago, but we believe the sheer size of the increase is further proof the condition of our roads is worsening. With over half a million potholes reported in 2017 and a more accurate figure for all authorities, including those that didn’t provide data, likely to be in excess of 674,000, this is sadly just the tip of the iceberg as thousands will go unreported every year.

“This means road users are then reliant on authorities finding these potholes in their regular inspections and taking action to fix them which in reality is probably less likely to happen. However, when road users report potholes the onus is on the authority concerned to fix them or risk suffering subsequent compensation claims as a result of not doing so.”

Drivers questioned for the RAC Report on Motoring listed the condition and maintenance of local roads as their top motoring concern with many saying the standard of roads is not good enough. Drivers also believe that conditions have worsened in the last year. The RAC’s data shows that since the third quarter of 2017 vehicle damage from potholes remained constant and there has been no significant improvement over the past 12 months.

“This is no doubt why the Asphalt Industry Alliance estimates the one-off investment required to return local roads in England and Wales to a fit-for-purpose standard to be over £9.3bn,” said Lyes. “In order to bring our local roads up to an acceptable and safer condition, they require long-term ring-fenced funding which the Treasury could do if they were prepared to set aside a fraction of the revenues that motorists pay through fuel duty,” Lyes said.