WHEN the windows of Canterbury Cathedral need cleaning, it is not a job for a man with a ladder, bucket and shammy leather.

Instead it's a painstaking task which requires many of the unique, stained glass panes to be removed and tackled by experts with special tools and materials.

Glass conservators are currently working on one of the Cathedral’s most spectacular windows, the South Oculus which dates from 1180 and depicts scenes from the Bible.

It has more than 50 panels, including some of the finest medieval pieces in the UK, all of which have suffered severe corrosion and are in urgent need of conservation.

Piece by piece they are being removed and replaced with temporary modern glazing while they are worked on.

Head of stained glass conservation Leonie Seliger said: "We cannot and would not want to clean the glass completely but our aim is to remove any loose material and prevent any further deterioration."

To ensure the magnificent 4.6 metre diameter Oculus it protected for the future, a scientifically-designed frame of protective glazing will be installed in front of the original window to protect it from the elements.

The work is part of the huge restoration project for the Cathedral for which a £50 million appeal has been launched. So far nearly £7 million has been raised.