The drawing measures nearly 14 metres and is divided into 10 panels. Conservators have been working on two panels at a time. They began by cleaning the surface of the drawing to remove 150 years of dust and dirt

The edges of the panels have been particularly vulnerable to damage over the years. Here Mari Watanabe uses handmade Japanese paper to fill in a small area where the paper has been lost

The strips of Japanese repair paper (shown here in the foreground) have been carefully coloured to match the 19th century paper used in cartoon

Tanya Millard undertakes another delicate edge repair. The figure shown is a ‘vivandière’, offering brandy to a dying soldier – one of only two women depicted in the scene

Clare Reynolds is using old flat irons as convenient weights, pressing repairs as they dry. On the right, Alice Powell uses a technique combining heat and moisture to gently flatten the paper

Ultraviolet light reveals the changes Maclise made to Blücher’s hat before the cartoon first went on display in 1859. It also shows later repairs, probably made in the 1930s after the cartoon had been on loan to the Royal Military Academy Sandhurst