Every year, schools across England weigh and measure children in Reception and Year 6 as part of the National Child Measurement Programme (NCMP). The citywide London figures are concerning enough on their own, but the real story is in the spread: some boroughs report childhood obesity rates two or three times higher than others, just a few miles apart. Understanding childhood obesity by borough is essential to reading London’s health data honestly, rather than treating the capital as a single, uniform population.
What the National Child Measurement Programme Actually Measures
The NCMP is a national public health surveillance programme, not a diagnostic screening tool for individual families. Each year, state-maintained schools in England record the height and weight of children in Reception (aged four to five) and Year 6 (aged ten to eleven), and the results are aggregated by local authority area — in London’s case, by borough. The Office for Health Improvement and Disparities (OHID), part of the Department of Health and Social Care, provides strategic leadership for the programme nationally, while individual local authorities are responsible for its delivery on the ground, commissioning school nursing teams to carry out the measurements.
The purpose is population-level monitoring: tracking whether obesity prevalence is rising or falling over time, and identifying which areas need targeted local action. Because the same measurement protocol is applied consistently across every borough, NCMP data is one of the few genuinely comparable, borough-by-borough health datasets London has — which is exactly what makes it useful for a publication built around plain-language, data-referenced borough briefings.
The London-Wide Picture: Above the England Average by Year 6
Citywide, London’s obesity figures run consistently above the national average, and the gap widens as children get older. In the most recent full year of data (2024/25), 23.2% of Year 6 children in London were classified as obese, compared with an England average of 22.2%. In the 2022/23 data, London’s Year 6 obesity prevalence (including severe obesity) stood at 24.8% against an England figure of 22.7%, and when overweight and obesity are combined, the figure for London Year 6 pupils reached 38.8% — nearly two in five children.
The picture for younger children is closer to the national average but still elevated: Reception-aged children in London recorded an obesity prevalence of 9.3% in 2022/23, against 9.2% for England, with 20% classified as overweight or obese when both categories are combined. The gap between Reception and Year 6 figures is itself informative — it suggests that whatever is driving excess weight gain in London children accumulates across primary school years, rather than being present from the earliest measured age.
The Borough Gap: Where Rates Are Highest and Lowest
The citywide average obscures a much larger range between individual boroughs. In the 2024/25 Year 6 data, Southwark reported the highest obesity rate in London at 29.7%, while Richmond upon Thames recorded the lowest at 12.1% — meaning a child in Southwark was, on this measure, roughly two and a half times more likely to be classified as obese than a child in Richmond upon Thames. Kingston upon Thames also reported a comparatively low rate, at 14.6%.
| Area | Year 6 obesity rate | Position |
|---|---|---|
| Southwark | 29.7% | Highest recorded borough rate |
| London average | 23.2% | Citywide (2024/25) |
| England average | 22.2% | National comparator |
| Kingston upon Thames | 14.6% | Among the lowest |
| Richmond upon Thames | 12.1% | Lowest recorded borough rate |
The broader pattern runs along familiar geographic lines. Boroughs in east and inner London are consistently found towards the higher end of the range, while the lowest rates cluster in the wealthier boroughs of south-west London. This is not a random distribution — it follows the same geography that shows up in other borough-level health data, from life expectancy to GP access.
Why the Gap Tracks Deprivation, Not Chance
NCMP data, alongside the wider public health literature it feeds into, consistently shows that children living in more deprived areas are significantly more likely to be classified as overweight or obese. This isn’t a single-cause relationship. Household income affects access to fresh food and to paid activities like swimming lessons or sports clubs; local environments affect how easy or safe it is for a family to walk or cycle rather than drive; and the density of fast-food outlets tends to be higher in lower-income neighbourhoods. Southwark’s position at the top of the range and Richmond’s at the bottom reflect this same underlying deprivation gradient that runs through most of London’s public health indicators, rather than any single local intervention succeeding or failing in isolation.
This is also why obesity prevalence tends to rise between Reception and Year 6 within the same borough. Six additional years of exposure to a local food environment, an activity environment, and a household economic situation compound over time — which is one reason public health teams treat the two measurement points as showing a trajectory, not two unrelated snapshots.
What Borough-Level Data Means for Local Health Planning
NCMP figures are used by local authorities and school health teams to plan where to direct prevention resources, from healthy-weight programmes to the school nursing capacity needed to deliver accurate annual measurement across every primary school in a borough. That delivery work itself depends on unglamorous but essential infrastructure: calibrated, Class III-approved medical scales and stadiometers that meet the accuracy standards public health measurement requires, maintained and checked on a schedule so that year-on-year comparisons remain valid. A borough with high obesity prevalence and a borough with low prevalence still need the same measurement rigour to know which is which — inaccurate equipment in either direction would distort the very comparisons this article relies on.
For readers trying to make sense of childhood obesity by borough, the underlying lesson is one that applies across London Health Infrastructure Review’s borough briefings more generally: a single London-wide statistic is rarely the most useful number. The borough-level breakdown is where the pattern — and the case for targeted local action — actually becomes visible.