Work has begun to fit solar panels at Gloucester cathedral in southwest England.
The cathedral, which originated in 678 or 679, will be upgraded with up to 200 panels to reduce its annual energy costs by 25% or "enough to make 2,000 cups of tea every day of the year".
Located on the south nave roof, 30m above the ground, the panels will be almost impossible to see.
A fundraiser that was announced for the project in August last year has raised 90% of the money needed.
Reverend Canon Celia Thomson said: "The installation of solar panels on this remarkable building is a historic moment.
"We are thrilled that our vision to become a greener cathedral is being fulfilled and proud to make a valuable contribution to the Church of England’s Shrinking the Footprint campaign."
Once the work is complete, the 1,000-year-old building will become the oldest cathedral in the UK, and possibly the world, to install a commercially sized solar panel system on its roof.
Image: Gloucester Cathedral (Wikimedia Commons/Saffron Blaze)