Lord Nelson HMS Victory letter to go under the hammer in Derbyshire

Auctioneer Charles Hanson says the original letter gives a "remarkable" insight into Lord Nelson's tactical and strategic skills

A letter written by Lord Nelson on his flagship HMS Victory - giving a "remarkable" insight into his naval tactics - is set to be sold at auction.

The letter, dated 28 April 1804, was written when Nelson was "attempting to lure the French and Spanish fleet out of Toulon to give battle".

Nelson did meet the enemy at the Battle of Trafalgar in 1805, where he was injured and died aboard the ship.

The three-page letter is expected to fetch between £20,000 and £30,000.

Nelson was killed by a French sniper while aboard the HMS Victory during the Battle of Trafalgar

Auctioneer Charles Hanson said the letter revealed Nelson relied on smaller vessels to "inform him should the French fleet leave the safety of the harbour".

The letter, addressed to Frank Sotheron - captain of HMS Excellent - states Nelson's wish for the captain to inform him of the movements of the French, saying: "In the event of their sailing... you will use every effort to communicate the same to me as early as possible".

Nelson chased the French fleet to the West Indies but did not have the chance to engage in battle until the following year.

Nelson had urged a captain to track a French fleet leaving Toulon

"This battle remains renowned for the tactical skill employed by Nelson and for his courage in leading the first column of British vessels into the attack, having sent the immortal signal: 'England expects that every man will do his duty'," Mr Hanson said.

The battle, which saw the Franco-Spanish fleet defeated, has been hailed as one of the most decisive naval battles of the Napoleonic wars.

Potential buyers will bid on the letter at Hansons in Etwall, Derbyshire, on Saturday.

The letter was written on board HMS Victory