Burgoyne also found himself short of troops. His original plan had called for 8,000 regulars, supported by 2,000 Canadians and 1,000 Indians, giving him a minimum of 11,000 troops along with a suitable level of artillery. Even with this number the expedition would have been risky, especially as Burgoyne was going to have to provide garrisons for the strongholds captured on his march, but the eventual numbers were somewhat lower. At the core of his army were 3,700 British regulars and 3,000 Germans, with a strong contingent of Brunswickers. This left him over a thousand men short of his original contingent of regulars. Worse was the lack of Canadian and Indian support. Only 650 local troops had been found to accompany him, along with a mere 400 Iroquois. Despite these problems, Burgoyne was still confident of success, buoyed by the high quality of his regular troops and their officers (of whom some thirty were later to become generals).
There were also problems on the American side. Chief of them was the struggle for command between Philip Schuyler, the unpopular commander of the Northern Department, and Horatio Gates, who had lobbied Congress for command of the Northern Department, and even been granted it for a brief period, before Schuyler was reappointed in May, just as Burgoyne was about to set off.
Although the easy capture of Ticonderoga was a major triumph, the American retreat disappointed the British, who had been hoping to inflict a major defeat on the Americans. Instead, the bulk of the American forces escaped, although Burgoyne nearly captured the American wounded as they sailed down the lake. There was a minor battle on 7 July at Hubbardton, when a British advance guard of 850 commanded by General Simon Fraser caught up with the American rear of 1,000 commanded by Colonel Seth Warner. Although they were retreating, the American withdrawal had not yet turned into a rout, and the outnumbered British were hard pressed until relieved by a contingent of Germans.
Burgoyne was now faced with the most critical period of his expedition. The Hudson was only twenty miles away, but the route from Skenesboro to the Hudson crossed the deep forest. Burgoyne had originally planned to return to Ticonderoga and take an alternative route down Lake George to an existing road to the Hudson. Instead, Burgoyne chose the forest route. The route followed Wood Creek, crossing it forty times. Schuyler blocked the road, destroyed the bridges and then retreated to the Hudson. Even without active opposition, Burgoyne's men took three weeks to cross the twenty miles to the Hudson. Finally, on 30 July the army reached the ruins of Fort Edward. They had reached the Hudson.
The arrival at the Hudson was the last British success. The slower than expected journey left the army short of supplies, with their numbers already depleted by the need to provide garrisons on their route, while the expected influx of Loyalists had failed to materialise. American morale was much boosted on 4 August by the replacement of Schuyler by the more popular Gates. The American army stopped shrinking and began to grow. Meanwhile, the second British expedition to the Mohawk river had stalled. When St. Leger reached Fort Stanwix at the head of the river, he found a garrison nearly as large as his own army and was forced to settle down to a siege. An American relief column under Benedict Arnold soon forced St. Leger to withdraw. Burgoyne was on his own.
In an attempt to relieve his supply problems, Burgoyne agreed to send out a raid east towards an American magazine at Bennington. Once again, the British were mislead by reports of large numbers of loyalists waiting for a chance to rise against the rebels. The expedition was a total disaster. The resulting battle of Bennington (16 August) cost the British at least 900 men and failed to solve their supply problem. However, the situation was not yet critical. The army was intact, and still had supplies for a month. Burgoyne could have chosen to retreat to Ticonderoga, or stay at Ford Edward, where he later claimed he would have been secure. Instead, he decided to march on towards Albany. He was later to claim he felt bound by his orders to meet with Lord Howe, but during August Howe was still in the early stages of his Philadelphia campaign. The only possible source of aid for Burgoyne was Clinton and the garrison of New York, who were still unaware of Burgoyne's situation.
Not only did Burgoyne decide to march south, but he also decided to cross the North River where he was, and march south on the western bank of the river. The American forces were already concentrated on this bank of the river, and Burgoyne's decision to cross over the river has been much criticized. By crossing the river he cut himself off from his retreat to Canada. However, crossing over the river at Albany would have been much harder than it was at Saratoga. On 13 and 14 September, Burgoyne and his army crossed the Hudson.
Facing him was Gates with an army of 6000 to 7000 men, at least as large as Burgoyne's own force. Moreover, the American army was still growing, while the British were losing strength all the time. On the same day Burgoyne crossed the river, Gates began to dig in on Bemis Heights, a strong position, although the Americans left their left flank curiously unprotected. From Saratoga, Burgoyne began to march south in three columns. On 18th September they made first contact with outlying American forces and on the following day the British advanced. The resulting first battle of Saratoga, or Freeman's Farm, was a disaster for the British. Although both sides suffered heavy losses, and the British held the heart of the battlefield, they could not afford their losses. The Americans in contrast were still gaining strength.
The British were still not entirely isolated. Some messages still passed between Clinton in New York and Burgoyne. Ten days after Freeman's Farm, Burgoyne wrote to Clinton attempting to pass command to him. Clinton had just received reinforcements, and aware that Burgoyne was in desperate straits decided on a dash up the Hudson River. On 3rd October he launched his expedition, which on 4th October captured the Hudson forts. In a letter written on 8th October Clinton expressed his hope that his successes would help Burgoyne.
Sadly for the British, Burgoyne had fought and lost another battle on the previous day. Second Saratoga, or Bemis Heights (7 October), developed from another British attack into a devastating American victory. Burgoyne was forced to withdraw to Saratoga.
Even the eternally optimistic Burgoyne was now aware he was faced by defeat. On 8th October the remains of his force reached Saratoga, where on 12th October they were finally surrounded. The British camp now found itself under a severe bombardment, with their only hope the rescue attempt from New York that had already stalled. Burgoyne now entered into negotiations with Gates. His proposal was that his army would surrender their arms and march out with honours of war. They would then be taken to Boston, from where they would return to Europe, not to return to America until after the war. This was acceptable to Gates, and on 17 October the British marched into captivity.
The two armies made an interesting contrast. Hardly any of the Americans had a recognisable uniform, one British officer describing them as wearing the cloths 'in which he goes to the field, the church or to the tavern'. The officers had uniforms of a sort, but each one different, possibly reflecting their service in the various state militias. In contrast, the British and Germans had retained their uniforms, although many were tattered. Much to the surprise of the American troops, many of the British officers had managed to keep their dress uniforms in pristine condition. The victorious Americans greeted their new prisoners with a respectful silence.
The disaster at Saratoga all but ended Burgoyne's military career. He returned to Britain to face the most severe criticism from all sides, apart from the Whig opposition, who unsurprisingly supported him. However, the army was only ever part of his life, and he returned to his role in London society and as a talented playwright.
Unsurprisingly, Gates was raised to the level of American hero. Saratoga was the first major American victory of the war. In contrast, Washington had suffered a series of defeats and failed to prevent the capture of Philadelphia. During the bitter winter of 1777/8 at Valley Forge many, including Gates, saw him as a far better candidate for the overall commander than Washington. Luckily for the American cause, Washington remained in charge, while Gates was eventually to lose his reputation after defeat at the battle of Camden (1780)
Saratoga also played an important part in the career of Benedict Arnold. Finally promoted to Major-General, his wounds prevented him from further active service. He was given a job in Philadelphia, but soon managed to break some minor regulations. The bitterness over what he saw as his harsh treatment began the process that saw him return to British allegiance.
News of the American victory played an important role in the French decision to come out openly on the American side. From early 1776 the French had been supplying munitions to the Americans, although they were always worried that the colonists and the British would at some point unite against them. On the American side there was still a fear of replacing British masters with French or Spanish masters, who would be even less acceptable to the colonists. During 1777 negotiations began for an alliance between the United States and France. However, they were not going well, and on November news of the fall of Philadelphia seemed to have ended any chance of success. Soon after, on 4 December, news of Saratoga reached Paris and French interest in an alliance was renewed. On 17 December the Franco-American alliance was agreed. Surrender at Saratoga now left the British facing an world conflict. All realistic hopes of victory in America were gone.
Predictably, the defeat led both to a crisis of confidence and a political crisis in Britain. The Whig opposition was given the ammunition it needed to launch an attack on the government's handling of the war, led in the Lords by Lord Chatham (William Pitt the elder), Prime Minister during much of the Seven Years War, and in the Commons by Charles James Fox, whose attack was so well directed that no government minister dared respond. Fox even suggested that recognising American independence might be good for British interests. While his motion not to send any more existing army units to American was defeated, the Government majority was much depleted. As he had before, Lord North attempted to resign, although when George III reluctantly agreed to this, North rediscovered his enthusiasm for the job.
What anti-war momentum there was in Britain disappeared as soon as it became clear that the Americans were about to ally themselves with France. The news of looming French involvement led to a rash of new units being raised, including several now-famous highland regiments. After an initial period of gloom, Britain was probably now more united behind the war effort than at any other time.