A church has tried a new way of deterring metal thieves - by having invisible markers installed in the lead on its roof.
Engineers used guns to shoot coded micro-dots into the roof of St Peter's Church in Huddersfield.
The York-based company, Trace-in-Metal, said any lead stolen from the church's roof could be traced back, even if it was melted down.
The Diocese of Wakefield said metal theft was a "continuing problem".
John Minary from Trace-in-Metal said: "Because the dots are embedded in the lead and survive smelting, the deterrent lasts throughout the recycling food chain."
The technology was installed at St Peter's as part of recent renovation work, although the church has not been targeted by metal thieves before.
The Church of England said nationally it was the victim of more than 10,000 cases of metal theft between 2007 and 2012, costing £27m to repair.
Archdeacon of Pontefract, Peter Townley, said: "We've had various schemes to try to combat this, such as smart water and roof alarms, but it's a real pain.
"When a church is a victim of metal theft there is a limit to how much we can claim.
"It's not just the cost of the lead, but if it rains there's the damage caused to things like the organ, or stained glass windows."
The government has introduced new laws to tackle metal theft.
Cash payments for metal at recycling yards were banned in December, and from this autumn scrap metal dealers will be required to hold a licence.