<P> With the advent of the Industrial Revolution, goods produced by slavery became less important to the British economy . Added to this was the cost of suppressing regular slave rebellions . With support from the British abolitionist movement, Parliament enacted the Slave Trade Act in 1807, which abolished the slave trade in the empire . In 1808, Sierra Leone Colony and Protectorate was designated an official British colony for freed slaves . Parliamentary reform in 1832 saw the influence of the West India Committee decline . The Slavery Abolition Act, passed the following year, abolished slavery in the British Empire on 1 August 1834, finally bringing the Empire into line with the law in the UK (with the exception of St. Helena, Ceylon and the territories administered by the East India Company, though these exclusions were later repealed). Under the Act, slaves were granted full emancipation after a period of four to six years of "apprenticeship". The British government compensated slave - owners . </P> <P> Between 1815 and 1914, a period referred to as Britain's "imperial century" by some historians, around 10,000,000 square miles (26,000,000 km) of territory and roughly 400 million people were added to the British Empire . Victory over Napoleon left Britain without any serious international rival, other than Russia in Central Asia . Unchallenged at sea, Britain adopted the role of global policeman, a state of affairs later known as the Pax Britannica, and a foreign policy of "splendid isolation". Alongside the formal control it exerted over its own colonies, Britain's dominant position in world trade meant that it effectively controlled the economies of many countries, such as China, Argentina and Siam, which has been described by some historians as an "Informal Empire". </P> <P> British imperial strength was underpinned by the steamship and the telegraph, new technologies invented in the second half of the 19th century, allowing it to control and defend the empire . By 1902, the British Empire was linked together by a network of telegraph cables, called the All Red Line . </P> <P> The East India Company drove the expansion of the British Empire in Asia . The Company's army had first joined forces with the Royal Navy during the Seven Years' War, and the two continued to co-operate in arenas outside India: the eviction of the French from Egypt (1799), the capture of Java from the Netherlands (1811), the acquisition of Penang Island (1786), Singapore (1819) and Malacca (1824), and the defeat of Burma (1826). </P>

How many country did the british empire rule