George Alagiah reports on the history of mixed-race Britain. Before the First World War Britain's ports hosted communities of merchant seamen living in boarding houses, segregated from the local community. The First World War saw the increase of numbers of foreign merchant seamen and by the end of the war many had formed relationships with local women and decided to stay. In 1919 rioting broke out in some ports, a violent reaction by white men to the relationships between the non-white men and local women. Relatives describe the experiences of prejudice and intolerence their families faced. Studies were conducted on mixed-race children to see if there was a link between appearance and intelligence and whether they could 'pass as English'. In the 1930s the mixed race communities grew, such as in Tiger Bay in Cardiff, sharing customs. However, there was opposition to the mixed race community but proposals to ban sex between races were not introduced.