A late 12th century stained glass window at Canterbury Cathedral has been put back in place after painstaking conservation.

It has taken three conservators 18 months to restore the window, which depicts four apostles – St Peter, St Stephen, St Paul and St Barnabas.

The ornamental borders of the window date to 1180, while the figurative panels are restorations dating to the 1850s.

Parts of the window have survived in situ for more than 800 years.

The condition of the medieval glass was poor, with serious corrosion to the glass and to the original painted decoration.

The panels were removed from the frame, carefully cleaned with tiny sable brushes under the microscope and fractures were mended. Loose paint flakes were consolidated.

The window is now set behind an outer protective glazing which will prevent new corrosion from forming.