There has been a significant deterioration in the condition of unclassified roads in towns and cities.

In addition, it has been found that the ability of road surfaces to prevent cars skidding was below standard on a quarter of all major roads in England and almost half of all London’s roads.

The findings are contained in a report - Transport Statistics Bulletin Road Conditions in England 2007 – produced by the Department for Transport (DfT), which provides the most up-to-date picture of the state of roads in England.

It said the majority of the roads that had deteriorated the most – such as residential streets – had suffered from “whole carriageway major deterioration”, which accounted for almost half of the defects.

This is defined as the carriageway being affected by problems such as cracking, loss of aggregate, deformation or defective patches.

The number of potholes was reported separately and, according to the report, occurred on average of one every 200m on some roads.

The report also found that almost a quarter of major roads in England needed further investigation because of the questionable level of skidding resistance the road surface offers.

This rises to almost half of all roads in London and to 26% in other cities.

Road surfaces on motorways were the best at preventing skidding.

The results for motorways also showed that the percentage of the network that needs maintenance has been broadly constant over this period, at around 6%.

The condition of all purpose trunk roads has been improving over the last five years; the percentage of all purpose trunk roads that may need maintenance decreased from 7% in 2006 to 5% in 2007.