Four gully cover grates have been stolen from Dagger Road and seven from Morside, both at Treales, all from within the carriageway.

And six manhole covers have been stolen from the A588 Shard Lane at Singleton, all from the footway.

United Utilities have also warned of the serious dangers of tampering with overhead lines or breaking into substations.

Meanwhile, police across the UK targeted metal thieves last week in a two-day operation against a crime said to be costing the economy £360m every year.

Church roofs – for their lead – are said to be prime targets, too.

Stealing manholes and grid covers is not only costing taxpayers, but is a safety hazard for pedestrians, cyclists, horse riders and drivers.

County councillor Matthew Tomlinson, cabinet member for sustainable development, said: "The problem is that members of the public see a van turn up and a couple of men in fluorescent jackets putting cones out, so they presume it's all above board."

Vicar and Area Dean, the Reverend Fr Damian Porter, said: "If anybody sees anybody around a church that looks like a workman out of hours they should ring the police.

"The community needs to stand together. It is not just churches but other community buildings.

"Members of the public need to stay vigilant. It is a constant concern to anybody who has large amounts of metalwork on buildings."

United Utilities asked residents to get in touch if they spot anything suspicious.

A spokesperson said: "This issue is of major concern.

"By tampering with overhead lines or breaking into substations, these thieves are putting themselves at risk of fatal electric shock, endangering the public and disrupting power supply."

Anyone with information should call 0845 0530011.