A FORMER officer of Her Majesty’s Bodyguard has published a biography telling the story of a key figure in the Battle of Waterloo.

Warminster author Colonel Sir William Mahon was one of the elite guards who stood at the lying-in-state and at the funeral of the Queen Mother.

His book ‘Waterloo Messenger’ tells the story of Henry Percy, a young and largely forgotten officer who carried the Waterloo Dispatch, the Duke of Wellington’s account of the Battle of Waterloo, back to London in June 1815.

A French army under the command of Napoleon Bonaparte was defeated by two of the armies of the Seventh Coalition: an Anglo-led Allied army under the command of the Duke of Wellington, and a Prussian army under the command of Gebhard Leberecht von Blücher, Prince of Wahlstatt.

Sir William’s interest in the subject was sparked as a boy listening to a great aunt who had ancestors at the Battle of Waterloo, which was fought on 18 June in present-day Belgium, then part of the United Kingdom of the Netherlands.

He said: “She was impossible to buy birthday presents for but one year we found a nice, if not wholly accurate, booklet about the Waterloo Dispatch and she was entranced by it.”

It was towards the end of his military career that he began finding out more about the battle and the young Henry Percy, who served with the 7th Royal Fusiliers and with the Duke of Wellington in Paris.

Henry Percy was an Aide de Camp to Sir John Moore and carried Sir John to his grave after the Battle of Corunna on 17 January 1809. He later transferred to the 14th Light Dragoons in 1810 and died in April 1825 aged 39.

Sir William’s research led him to the original journal of Henry Percy with his account of the wounding and death of Sir John Moore; and to French archives showing Henry Percy’s father was one of Napoleon’s VIP hostages.

He discovered that while a prisoner of war, Henry Percy had a girlfriend in France and that their illegitimate son, Major General Sir Henry Marion Durand, became a celebrated British Indian Army general who was killed falling off an elephant on New Year’s Day 1871.

Sir William said: “It has been like putting a jigsaw together, only a jigsaw without a box with a picture and with all the pieces face down, with many missing and only to be found abroad.

“I did the research out of interest then thought I would put together a book as a way of keeping all the research together. It has been a fascinating challenge, but a retirement labour of love.”

‘Waterloo Messenger’ by William Mahon is published by Pen and Sword, price £25, www.pen-and-sword.co.uk.