England expected and Robert Hope did his duty: days before the 205th anniversary of one of the most famous of all naval battles, an eyewitness account of the battle of Trafalgar has resurfaced – written by an ordinary sailor who viewed history in the making from the heat, smoke and stink below decks. He writes:

What do you think of us Lads of the Sea now, I think they won't send their fleets out again in a hurry

Hope, a 28-year-old sailmaker, bragged from HMS Temeraire, which was in the thick of the battle. The letter "hoping will find you in good health as I bless god I am at present", was written to his brother John, safely ashore at Ashford in Kent. Although the National Maritime Museum has voluminous accounts of Nelson's victory and death at Trafalgar in its archives at Greenwich, it is a rare voice from below decks – reports of any battle are invariably dominated by the officers. Hope described how his ship engaged the Spanish four-decker Santísima Trinidad, alongside Nelson's flagship Victory, but was soon caught in a firestorm, and surrounded by French ships.

When five more of the enemy's ships came upon us and engage us upon every quarter, for one hour and sixteen minutes, when one struck but being so closely engaged that we could not take possession of her at that time, two more seemed to be quite satisfied with what they had got so sheered off, but the other two was determined to board us. So with that intent, one dropt on our starboard side called the la Fue and the other dropt on our larboard side called the Doubtable, they kept a very hot fire for some time. But we soon cooled them for in the height of the smoke our men from the upper decks boarded them both at the same time, and soon carried the day.

A letter from Robert Hope to his brother. Illustration: National Maritime Museum

Despite a few crossed out mistakes, the letter is beautifully written. Quintin Colville, curator of naval history at the museum, said: "It instantly demolishes the cliched view of life below decks as villainous and ignorant – this man was obviously highly educated, and he gives a most vivid and lively description."

Colville says Hope would have joined a gun crew for the battle.

"The gun deck would have been a vile place, terrifying, deafening, highly dangerous, with great splinters flying from where the balls hit – we think of a splinter as something under your fingernail, but these could be chunks of wood two feet long that would disembowel a man."

He is not surprised Hope never mentions the tragedy amid the victory, the death of Nelson. "For an ordinary sailor his ship was his whole world – and not even the ship, but the crew immediately around him that he lived and worked with, and that is how he would have experienced the battle, from within that closed world."

Hope knew he was lucky to be alive, unlike Nelson and 458 other British casualties, and almost 3,000 casualties on the French and Spanish ships.

We had forty three Killed and Eighty five wounded, and twenty seven drowned in the Prizes.

Counted when Smoke Cleared away Seventeen Prizes and one all on fire, but we have only got four into Gibraltar, for a Gale of wind came on the day following that we was obliged to scuttle them for they was so very leaky.

The sunken prize ships were a grievous loss: even the humblest sailor could expect a few shillings as his share if they had survived.

Hope was still on board, moored off Portsmouth, when he wrote. The letter ends with tender greetings to his sister and father:

… please to let him know that I am arrived in England for I long very much to hear from him.

The letter has remained in the family until now, treasured. It cost us a considerable amount of money, but it was worth every penny," Colville said. "This is such a rare thing, a voice from the lower decks. It will be very well used here – and eventually we hope to be able to flesh it out with a full biography of Robert Hope. We don't know what happened to him in the end yet, but he survived 21 October 1805 with both his arms and legs intact, and that was a very considerable achievement."

The artist JMW Turner provided a poignant footnote to the story, in a painting now in the National Gallery and once voted the nation's favourite. Usually just known as The Fighting Temeraire, its full title is The Fighting Temeraire Tugged to her Last Berth to be Broken up, 1838. The painting shows the great ship on the Thames, still beautiful though by then too rotten even for her ignominious last service as a "hulk" floating prison, silhouetted against the sunset, as a dirty little steam tug boat tows her to a yard to be broken up for scrap.

Turner's The Fighting Temeraire. Image: Corbis

• This article was amended on 20 October 2010. The original article referred to the Spanish four-decker as Santa Trinadada. This has been corrected.