The first stage of the strategy was partially successful. On 11 January 1805 a squadron of French ships under the command of Admiral Missiessy slipped out of Rochefort in a snowstorm, crossed the Atlantic, and captured Martinique and the small islands of Nevis, St Kitts and Montserrat. However when they returned to France in May they found Napoleon outraged that they had not also taken Dominica, Barbados and St Lucia. Meanwhile Villeneuve had made a sortie out of Toulon on 14 January with a fleet of eleven ships of the line and several frigates. He had been driven back by storms but on 30 March 1805 he was encouraged by favourable winds to make a second attempt.
He managed to evade Nelson's Mediterranean fleet, which was re-victualling in Majorca, and sailed through the Straits of Gibraltar to Cadiz, where he ordered some of the ships of the Spanish fleet to put to sea and follow him to the West Indies. The French fleet arrived in Martinique on 14 May and the Spanish ships arrived two days later. When Nelson learnt from his watching frigates that Villeneuve and a large French fleet was at sea, he set off in pursuit, just as Napoleon had planned. In the Gulf of Cadiz he found that the enemy fleet had headed out across the Atlantic. Although they had a month's lead on him, Nelson immediately headed west and arrived at Barbados on 4 June He chased from island to island, and off Montserrat he received information that the French were intending to attack Antigua. But when he arrived at Antigua on 12 June there was no sign of them.
Villeneuve and his fleet had set off for France four days earlier. On 8 June his fleet had intercepted and captured a homeward-bound convoy of fifteen British merchant ships. This was a lucky break but when he learnt from the merchantmen that Nelson was in the West Indies, and was searching for him with a fleet of warships, he seems to have lost his nerve. He had received orders from France to capture Antigua, Grenada and other islands but he now abandoned his mission and headed for home. On 22 July in misty conditions off Cape Finisterre he encountered a fleet of fourteen British ships of the line under the command of Vice-Admiral Sir Robert Calder. A confused and inconclusive battle took place which came to be known as Calder's Action. The British captured two ships but failed to prevent the remainder of the French and Spanish ships from escaping in the mist and seeking refuge in the port of Vigo. Calder had to face a court martial later for failing to bring about a decisive action but at least he had successfully prevented the enemy fleet from heading up the Channel.
Napoleon had hoped to launch his invasion between 10 June and 10 July and was getting impatient. On 3 August he arrived at Boulogne to supervise the embarkation of the troops, and sent increasingly urgent letters to his admirals. He urged Villeneuve to 'sweep everything before you, and arrive in the Channel, where we are anxiously awaiting you ... If you are here for three days, indeed if you are here only for twenty-four hours, your mission will be accomplished.' And to Admiral Ganteaume at Brest he wrote, 'I wish you to put to sea at once, for the fulfilment of your mission, and to proceed with all your forces to the Channel . . . Start at once, and come here. We shall have avenged the insults of six centuries. Never have my soldiers and sailors risked their lives in a nobler cause.'
The British took the invasion threat extremely seriously, particularly in the southern counties which were most vulnerable to attack. Their cruising frigates could see the enemy's vast encampment on the hills above Boulogne, and from the cliffs at Dover and Folkestone the people watched the comings and goings of brigs and luggers and gunboats as the invasion flotilla was assembled. The countermeasures undertaken in Britain were impressive and would have made it extremely difficult for the French forces to effect a landing; without massive loss of life. Lord St Vincent, who had been appointed First Lord of the Admiralty in 1803, was responsible for the sea defences of the kingdom. He established a triple line of maritime defences. The first line consisted of frigates and gun-vessels which were deployed along the French coast to blockade all French shipping in port, including merchantmen and fishing boats. The second and most formidable line of defence was a squadron of warships based in the Downs whose job it was to intercept and attack the invasion forces if and when they escaped the blockading ships and put to sea. The third line of defence consisted of gunboats and armed fishing vessels stationed in all the harbours, estuaries and inlets along the south and east coast of Britain. They were manned by the Sea Fencibles, the body of volunteer sailors and fishermen set up by Lord Keith during the previous emergency in 1798 and re-established following the end of the Peace of Amiens. To protect the Thames a line of old warships was anchored across the lower reaches with orders to link up and form a continuous barrier in the event of an impending invasion.
Behind the sea defences were the land defences. The most visible of these were the Martello towers. These were based on the design of a fort at Cape Mortella in Corsica which had impressed the navy and army engineers by standing up to prolonged bombardment from ship and shore in 1794. More than a hundred of them were built between Seaford in Sussex and Aldeburgh in Suffolk; some forty of them remain today as the most visible reminder of the Napoleonic threat to Britain.
In addition to the Martello towers there were batteries of guns established overlooking beaches and landing places. Existing forts and castles, like those at Dover and Walmer, were strengthened and manned with troops. If and when the invasion was imminent the news would be spread by the lighting of beacons on hilltops and the ringing of church bells; details would be transmitted by the chain of wooden shutter telegraph stations which linked the Admiralty with the dockyards at Chatham and Portsmouth. The regular army had around 80,000 men stationed in Britain at the resumption of hostilities and this was augmented by the militia and by volunteer regiments. Recruiting offices were inundated with men and boys wishing to join up. Although large numbers had to be rejected because they were too old, too young or hopelessly unfit, it was reckoned that by 1804 some 380,000 men, or 7 per cent of the adult male population, had joined the militia.
The descriptions of the army manoeuvres which took place on the hills and valleys of Kent, Surrey and Sussex suggest that they were a source of entertainment to the local population as well as those who took part. Sham fights were particularly popular. On 2 August 1805, for instance, several regiments took part in a fight under the orders of the Earl of Harrington. The main body of the troops was stationed at Dulwich with small groups of men on Denmark Hill, on the village green in Half Moon Lane and at the cross roads by the Half Moon public house. After the fight the men marched past and saluted the Earl of Harrington and then settled down for a picnic. According to The Times, 'The Earl and Countess of Harrington, and other ladies and gentlemen partook of a cold collation in a large marquee pitched at the entrance of the common. Great numbers of spectators were present.' The royal family meanwhile were going about their usual business. The King, the Queen and the princesses were staying in Weymouth where they attended the theatre, and went for cruises on the royal yacht. The Prince Regent was in Brighton attending the races. On 30 July his horse won the Egremont Stakes by a neck, and afterwards he went to a ball with his mistress, Mrs Fitzherbert. Three weeks later he was still in Brighton and, together with a number of noblemen and gentlemen, he watched 6,000 troops from Lewes, Shoreham and the surrounding area skirmish across the South Downs.
While the regular army and the volunteer soldiers carried out military exercises, and the Sea Fencibles kept watch from every signal station, clifftop and harbour entrance, the British Navy continued to blockade the French ports and guard the entrance of the Channel. It was the vigilance and constant presence of the warships cruising off the coasts of France and Spain which was the greatest obstacle to Napoleon's plans. This was the period when the ships truly earned the title of 'the wooden walls of England'. On her return from the West Indies in the late summer of 1804 the Bellerophon once again became part of those wooden walls. She joined the squadron blockading the port of Brest, and for seven months she endured the familiar hardships and perils of the rock-strewn coast of Brittany with its fierce tidal streams, overfalls and breaking seas. On 24 April 1805, while she was back in Plymouth taking on water and provisions in between cruises out to Ushant, Captain Loring was replaced by Captain John Cooke, the man who would command her at Trafalgar. Cooke was forty-two and had been in the navy since the age of eleven. He had seen action in the East Indies and then in the West Indies where he had fought at the Battle of the Saints. Later, when captain of the Nymphe, a 36-gunner, he had taken part in the daring capture of two French frigates within sight of the French fleet at Brest, an action commemorated in a sparkling painting by Nicholas Pocock.