Sea power underpinned an empire based on the usual power-building common to all countries, but also the racist assumptions of colonialism. There was, however, one bright point of moral light in the navy’s role. In 1807, having played a prominent role in the slave trade, Britain outlawed it. For the next few decades the Royal Navy actively pursued slave traders, liberating about 150,000 people, while the government paid subsidies to African chiefs to persuade them to end the practice. Slavery itself, though, continued to be ‘legal’ (although it never had been within Britain itself), but in 1833 was made illegal throughout all parts of the world controlled by the UK.