A wet winter has been blamed for the backlog of pothole repairs on Lancashire’s roads.

County highways boss Councillor Rupert Swarbrick said the authority is experiencing “significant and unprecedented reports of structural defects” across its road network.

He told a County Hall cabinet meeting groundwater levels in some areas were forcing repair materials out of filled-in potholes.

Water seeping into the surface of carriageways is the main cause of potholes – but wet weather also makes them difficult to fix.

New figures show the county council was falling short of some of its own targets for the time taken to repair potholes at the end of last year.

In the three months to December, the authority filled in 70 per cent of highway defects classed as urgent within the two-day timeframe it sets for itself – but the target is 90 per cent.  

Meanwhile, 83 per cent of non-urgent issues were put right within 10 days, again against a 90 per cent target.

But the county council did manage to repair 99 per cent of 'emergency' defects within a four-hour target.

Acting Labour opposition group leader, Cllr Jennifer Mein, accused the authority of missing some of its pothole targets “quite severely”.

County Cllr Swarbrick said it had rained on 71 of the last 93 days in Lancashire.

“Fixing potholes on wet days isn’t good and it makes our job very difficult to do,” he added.

“We are catching up now and this last week has seen a significant amount of additional activity.

"So you’ll find over the next few weeks, as the weather dries up, we will be catching up with that backlog."

Three roving teams of 'find-and-fix' repair workers had recently been deployed.

Councillors also approved a new four-year £2.4m deal for a firm to carry out a pothole repair technique known as 'spray injection patching'.

Asked by Cllr Mein whether the method ensured “a permanent job”, County Cllr Swarbrick said that was always the intention with pothole repairs.

But he warned “very high groundwater” in the west was posing further problems in the perennial pothole battle.

“The groundwater has actually been coming up from the bottom of the potholes and lifting the repairs out – and there’s nothing we can do to stop that, we just have to keep going back to make them good.

“But I’ve been and seen the process myself and it’s as good a system as we can come up with at the moment,” he added.