In his review of the television documentary Welcome to the Mosque (3 October), John Morrish asserts that the East London Mosque in Whitechapel is “the country's oldest”. Britain’s oldest purpose-built mosque is generally thought to be the 1889 Shah Jahan in Woking. The East London Mosque has gone through several incarnations, the earliest of which was commissioned in 1941 (though, as a community, one can argue that it has existed in some form since the 1910s). Edmund T. DeanRe