Lord Nelson's Battle of Trafalgar sketch discovered in scrapbook

The sketch includes lines showing the wind direction

A hand drawn map by Admiral Lord Nelson showing his plan to defeat the French and Spanish navies at the Battle of Trafalgar has been discovered.

The sketch shows his plan to split his fleet into three divisions to break and destroy the enemy line coming out of Cadiz harbour in Spain.

The drawing had been tucked inside a scrapbook for almost 200 years.

The "astounding discovery" has been donated to the National Museum of the Royal Navy in Portsmouth.

The map was found by historian Martyn Downer in the scrapbook dating from the 1830s, which was recently sold at auction.

It includes lines showing the wind direction, as Nelson's plan was to attack across the wind, taking advantage of the increased speed.

Lord Nelson was killed during his victorious battle

The drawing was found alongside an address leaf with Nelson's signature on it, dated September 5 1805.

"This fragment of pencil sketch is simultaneously a very intimate and vivid artefact, giving us an exceptional insight into Nelson's thinking and planning ahead of the battle," Mr Downer said.

The map had been inside a scrapbook for almost 200 years

Prof Dominic Tweddle, the museum's director general, said: "This is an astounding discovery.

"It shows that Nelson had thought deeply about how he would defeat the combined French and Spanish fleets long before he ever set foot on HMS Victory."

An address leaf in the book had Nelson's signature on it

The sketch will be on display on Monday to mark the 214th anniversary of the Battle of Trafalgar.

It will then be on permanent exhibition from next spring in the museum's refurbished Victory Gallery.

Nelson was killed during his victorious battle off the southwest coast of Spain on 21 October 1805.