Bangladeshis are one of the largest immigrant communities in the United Kingdom. Significant numbers of ethnic Bengali and ethnic Sylheti peoples arrived as early as the 17th century, mostly as lascar seamen working on ships. Following the founding of Bangladesh in 1971, a large immigration to Britain took place during the 1970s, leading to the establishment of a British Bangladeshi community. Bangladeshis were encouraged to move to Britain during that decade because of changes in immigration laws, natural disasters such as the Bhola cyclone, the Bangladesh Liberation War against Pakistan, and the desire to escape poverty, and the perception of a better living led Sylheti men bringing their families. During the 1970s and 1980s, they experienced institutionalised racism and racial attacks by organised ultra-right fascist groups such as National Front and British Nationalist Party.
Throughout the 17th to early 20th centuries, the British East India Company employed over thousands of South Asian lascars and workers, who were mostly Sylheti Muslim and Punjabi Sikh, to work on British ships. Due to the majority of early Sylheti settlers being lascar seamen, the earliest Muslim communities were found in port towns. Naval cooks and waiters also came. One of the most famous early Bengali Muslim immigrants to Britain was Sake Dean Mahomet, a captain of the British East India Company. In 1810, he founded London's first Indian restaurant, the Hindoostane Coffee House. He is also reputed for introducing shampoo and therapeutic massage to the United Kingdom. There are other records of Sylhetis working in London restaurants since at least 1873. At the beginning World War I, there were 51,616 South Asian lascars working on British ships, the majority of whom were of Bengali descent.