Admiral Baldwin Walker, the Surveyor of the Navy, was not convinced that ironclad warships would ever completely replace wooden ones but he recognised that the safety of the country depended on bettering the French threat as soon as possible.

The simple solution first suggested was to clad existing ships in iron. However Sir John Pakington, the First Lord of the Admiralty, supported the building of iron-hulled ships and, in November 1858, he commissioned a design.

The new ironclad was to be called Warrior after a distinguished third rate ship-of-the-line which had recently been broken up.

Warrior and her sister ship Black Prince were the fastest, largest, strongest and most powerfully- armed warships in the world, and confirmed Britain's place as the ruler of the waves.

It was a time of transition from sail to steam and Warrior would prove to be one of the fastest ships of her day.

"I often wondered how I mustered sufficient courage to order such a novel vessel" Sir John Pakington, First Lord of the Admiralty.

Isaac Watts, Chief Constructor to the Navy, and his assistant Joseph Large, developed an entirely new concept in warships. Their revolutionary idea was to house the main guns, boilers and engine in an impregnable armoured 'box' or citadel.

This was to be constructed from 4 ½ inch thick wrought iron plates bolted to 18" inches of teak, then mounted on the 1 inch thick plating of the hull itself, behind which were the frames and timber lining. In all this represented a total thickness of some 2 feet.

The bow and stern were added to each end of this well-armoured box and were constructed of wrought iron plates 1 inch thick. Watertight compartments were formed to limit the spread of water inside the ship, the first time this technique - soon to become worldwide practise - had been used in a warship.

Portsmouth and Chatham Royal Dockyards were not equipped to build iron hulls, so the contract went out to tender and was won by the Thames Iron Works and Shipbuilding Company based at Blackwall, London.

The plan was to complete the ship in nine months, but delays added 10 months. The Thames Iron Works had to be rescued from bankruptcy by the Admiralty during construction and work was made even more difficult by the coldest winter for 50 years.

"I often wondered how I mustered sufficient courage to undertake its construction".Mr Peter Rolt, Chairman, Thames Iron Works and Shipbuilding Company

As Warrior's sleek profile rose slowly from the (building) slip like some huge iron curtain the crowds gathered eagerly, fascinated by the ironclad's progress. Over 2,000 workers swarmed night and day over the wooden scaffolding which cocooned Warrior's vast hull, rising like a monolithic iron skyscraper. Newspapers and magazines reported with great enthusiasm on every development, one week waving the flag patriotically; the next, doubting whether she would ever float. A favourite topic was the cost which escalated to almost £400,000, twice that of a standard wooden ship-of-the-line.

Only 4 months after La Gloire was commissioned, Warrior was ready for launching and to make the Royal Navy the envy of the world.

Warrior was launched on 29 December 1860. It was the coldest it had been for 50 years and the dockyard, even the Thames, were covered in frozen snow.

Sizable crowds gathered to watch as Sir John Pakington named the ship, but even though braziers had been lit down both sides of the ship the night before, Warrior remained frozen on the slipway. Extra tugs and hydraulic rams were used, while on the upper deck hundreds of men ran from side to side to rock her free.

After 20 minutes, almost imperceptibly, she began to move, "God speed the Warrior" shouted Sir John, and broke a bottle of wine on her bow. The spectators cheered, hats were thrown in the air, tugs blew their whistles and the stern took the water 'as gracefully as any yacht'. Her Majesty's Ship Warrior was now afloat. She, and her sister ship, Black Prince, were to become the most feared ships afloat.

The morning after her launch, Warrior's red-painted hull sat high in the water as she was moved to the Victoria Docks for fitting out. A week after her launch the first member of Warrior's crew - Engineer William Buchan - was appointed to the ship, and by the end of January the Penn steam engine was part-assembled inside the ship. Steam was got up for the first time on March 1st whilst the fitting of the armour plates carried on for the next few months.

Fixing the armour plates to the side of the ship was a complicated job - each one had to be bent to fit the curve of the ship's hull before being tongued and grooved in order to fit closely to the plates around. In all some 202 armour plates had to be put onto the ship, weighing a total of 960 tons.

The masts and rigging were all supplied by Chatham Dockyard, and on April 15th the masts were lowered into the ship for the process of rigging to be begun on April 17th. When completed the 100-strong party of seamen sent from Woolwich had installed 25 miles of rope, 660 blocks and 80 hearts & deck eyes.

Along with these works, the myriad of other tasks needed to convert the empty iron hull into the world's most advanced warship were being undertaken: everything from the gunpowder magazine to the sickbay, and from the galley range to the wallpaper of the officer's cabins had to be fitted. Captain Cochrane commissioned the ship on August 1st, and a week later Warrior moved out of the Victoria Docks under her own power, and anchored a few miles down river at Greenhithe to continue fitting out and take on her guns and stores. It was during her time at Greenhithe that Charles Dickens visited the ship, writing later "..a black vicious customer as ever I saw. Whale like in size, and with as terrible a row of incisor teeth as ever closed on a French frigate."

With the finishing touches made, Warrior left the Thames for Portsmouth on September 19th 1861.