Fact check: What is the estimated number of Muslims in London as of 2025?

Executive summary — Direct answer: The most reliable, directly reported figure from the sources provided is the 2021 census count of 1,318,755 Muslims in Greater London, which makes Islam the city’s second-largest religion and equates to roughly 15% of London’s population in that census ^{[1] [2]}. None of the supplied analyses gives a standalone, verified 2025 count; available materials point to a UK Muslim population near 4 million and regional distributions that make London the single-largest Muslim concentration in England and Wales, but they stop short of producing an independently validated 2025 London total ^{[3] [2] [4]}.

1. What different sources actually claim — a mapped inventory of competing statements

The materials submitted present three recurring claims: a UK-wide Muslim population around 4 million, regional tallies indicating nearly 3 million Muslims in England and Wales in 2019, and a Greater London census count of 1,318,755 Muslims from the 2021 census ^{[3] [4] [1]}. Several summaries and reports repeat the UK 4 million figure and the England-and-Wales 2.96 million figure while noting that London contains the largest single regional Muslim share; however, those documents either omit a post-2021 London estimate or explicitly state they do not produce a 2025 figure ^{[5] [3] [4]}. The clearest, directly dated data point is the 2021 census Greater London count ^[1], and the other claims provide national or regional context rather than an updated city-level total.

2. Why the 2021 census number should be treated as the primary baseline

The 2021 census report is a full enumeration and supplies the city-level figure most frequently cited in the supplied analyses: 1,318,755 Muslims reported in Greater London ^[1]. Census counts are the gold standard for subnational totals because they avoid sampling error inherent in surveys and they provide a consistent reference point for subsequent estimates. Using the 2021 census as the baseline is important because the alternative figures in the packet — the UK total of roughly 3.99–4 million Muslims and the 2019 England-and-Wales estimate of 2.96 million — operate at different geographic scales and cannot, by themselves, produce a precise 2025 London tally without modelled adjustments ^{[2] [4] [3]}. The materials therefore anchor any 2025 discussion to that 2021 baseline ^[1].

3. Wider datasets mentioned and how they frame London’s share

The supplied documents repeatedly emphasise that the UK Muslim population is approximately 4 million and that Muslims are more geographically dispersed across local authorities than many other faith communities, with London having the single largest concentration by proportion ^[3]. Statista and other summaries in the packet show England-and-Wales totals and regional breakdowns for 2019 and earlier, reinforcing the pattern that London holds the largest regional Muslim population even if specific updated city totals are not released ^[4]. The Annual Population Survey and other ongoing sources are referenced but the provided analyses note these do not offer an authoritative London 2025 figure in the materials given ^[6].

4. Why producing a definitive 2025 figure is uncertain from these materials

None of the supplied analyses contains a direct, dated estimate for London in 2025; instead they offer either earlier counts ^{[7] [8]} or national/regional aggregates that require interpolation to reach a city-level 2025 value ^{[4] [1] [3]}. Factors such as migration flows, differential fertility, and internal movement into and out of London can materially change the count between 2021 and 2025; the provided sources explicitly decline to extend their numbers into 2025 without modelling or up-to-date survey results ^{[3] [6]}. Therefore any specific 2025 number would be a projection, and the documents at hand do not supply a transparent, reproducible projection methodology to justify a single point estimate for London in 2025 ^{[5] [6]}.

5. Best-supported conclusion, recommended figure and caveats for readers

Given the evidence in the supplied analyses, the responsible conclusion is that the most reliable, empirically grounded figure available here for Muslim residents of Greater London is the 2021 census total of 1,318,755, and that national-level totals of about 4 million Muslims contextualise London’s significance within the UK ^{[1] [3]}. If a 2025 headline estimate is required, the packet supports framing it as a projected range anchored to the 2021 census — for example, describing expectations that London’s Muslim population remains in the ballpark of 1.3–1.4 million, while explicitly noting that this is a projection and not a direct count because the provided materials do not supply a verified 2025 census or survey number ^{[1] [4] [3]}. Readers should therefore treat any single 2025 figure circulated without a clear methodology as tentative and await updated ONS releases or a new authoritative survey for confirmation.