The reasons that led the British to invade Australia were simple. The prisons in Britain had become unbearably overcrowded, a situation worsened by the refusal of America to take any more convicts after the American War of Independence in 1783. Crime rates were rising across the nation while large numbers of people were moving away from rural areas to the increasingly industrialised cities where unemployment ran high as machines replaced man power. An estimated one million people in Britain were below the bread line in 1788.