On the advice of Historic England, the Department for Digital, Culture, Media and Sport has upgraded 8 Brougham Terrace to Grade II*, which is reserved for “particularly important buildings of more than special interest”. (9–10 Brougham Terrace remains at Grade II.) The “special interest” refers to its historic status as Britain’s first attested fully-functioning mosque, which opened its doors to the public in December 1889. It is also significant for housing the first Islamic publication in Britain that we are aware of, the weekly Crescent, which started publication from the basement of №8 in 1893. Historic England acknowledged all this in noting the “recognition of its significance in telling the story of the emergence of Islam in England”.
Although the Shah Jahan Mosque was completed some months earlier in August 1889, it was not open for public use or for many of the functions normally associated with a mosque until Khwaja Kamal-ud-Din (1870–1932) established the Woking Muslim Mission there in 1913. Besides, the Liverpool Muslim Institute had rented an upstairs room at the Temperance Hall in Mount Vernon Street from either July or September 1887 — where there were Friday services, Sunday lectures to call people to Islam, and an Islamic study circle — until being kicked out by the landlord nearly two years later, who didn’t want Islam being taught and preached there, before moving to Brougham Terrace in December 1889. This upstairs room rented by this micro-community of Muslim converts in Temperance Hall was later described as “the first building used as a mosque” in The Crescent.
Here is a timeline of events based on the primary sources used by Ron Geaves and Jamie Gilham that verify the claim about Brougham Terrace as England’s first mosque.
 Out of the millions of buildings in England, there are over 9000 that are Grade I, nearly 24,000 that are Grade II*, and over 370,000 that are Grade II. The architect and academic Shahed Saleem should be given credit for working towards these new listings from behind the scenes, based in large part upon the work he has recently published: The British Mosque: An Architectural and Social History (Swindon: Historic England, 2018). At the same time as Brougham Terrace, three other buildings got listed too: the Shah Jahan Mosque got a Grade I, the Islamic Cultural Centre in Regent’s Park also got a Grade II* listing like Brougham Terrace, and the Fazl Mosque in Southfields got a Grade II listing. See H. Sherwood, “London Central Mosque given Grade II* Listed Status”, Guardian, 13 March 2018, https://www.theguardian.com/world/2018/mar/13/london-central-mosque-given-grade-ii-listed-status-historic-england, accessed 14 March 2018.