Kent’s housing targets: the demographic engine

Part 3 of 5 · Kent Water Investigation

This is Part 3 of a five-part Kent Local News investigation into the capacity of the county’s water supply, wastewater treatment, and chalk-stream environments to support the level of growth currently planned for the region. Part 1 set out the picture — 97 per cent of monitored water bodies in the Medway basin and 100 per cent in the Stour failing the Water Framework Directive’s “Good” test, the 53 per cent real-terms Southern Water bill increase across AMP8, and the regulator’s eleven-works warning. Part 2 examined the housing-capacity gap in detail — including South East Water’s written confirmation to Tonbridge & Malling Borough Council that it can supply potable water for 6,318 of the 19,620 homes the council is mandated to deliver by 2040. This Part examines the demographic arithmetic that produced those mandated numbers. Parts 4 and 5 follow on the next two Mondays.

Editor’s note: this Part was originally scheduled for Monday 18 May. Publication was held for one week so that* Kent Local News *could give appropriate care to a parallel investigation into the legal foundations of the Kent Local Government Reorganisation programme. The Mondays cadence resumes from this Part.

The number that nobody owns

In May 2024 the then-Department for Levelling Up, Housing and Communities — now the Ministry of Housing, Communities and Local Government — replied to a Freedom of Information request asking what data the department held on the proportion of mandated housing intended for residents of the local area in which it would be built. The department’s response, reference FOI2024/08392, confirmed that it does not hold five-year local residency or employment data for the areas to which housing targets are applied. The data does not exist within the department that sets the targets.

The same question put to Kent local authorities under the FOI Act has returned the same answer. Maidstone Borough Council (FOI/12883), Tonbridge & Malling Borough Council, Canterbury City Council and Kent County Council have each confirmed in writing that they do not hold equivalent five-year local-residency or local-employment data against their adopted Local Plan housing targets either.

The legally binding number is published. The basis on which it could be apportioned between local and incoming household formation is not.

How the Standard Method works

The Standard Method is the formula central government uses to assess local housing need. It begins with the Office for National Statistics’s most recent household projection for each local authority area, applies an affordability multiplier based on the ratio of local house prices to local earnings, and produces a single annual housing-need figure. That figure, summed over the plan period, is the headline mandated number councils carry through Local Plan adoption.

The formula does not distinguish between household formation arising from the existing local population and household formation arising from inward migration into the area. It does not distinguish between births to existing residents and births to recent arrivals. It does not distinguish between a household formed by a young person leaving the parental home in the same town and a household formed by a worker relocating from elsewhere. The output is the aggregate.

This is not an accidental feature. The Standard Method was designed to produce a uniformly applied national distribution, not a local-need accounting. The political defence of the formula has consistently been that it is mechanical, simple and not gameable. The cost of that design is that it does not answer the question councils are most often asked by their residents: how much of this is for us?

The fertility numbers in England

In May 2025, the Parliamentary Office of Science and Technology published POSTnote 745 — its briefing on the impacts of birthrate decline in the United Kingdom. The briefing draws on Office for National Statistics data and is the most recently published Parliamentary research summary on the topic.

The headline figures, all as cited by POSTnote 745:

Measure	Value	Source
Total Fertility Rate, England & Wales, 2023	1.44	ONS, the lowest on record since records began in 1938
Live births, England & Wales, 2023	591,072	ONS, lowest annual total since 1977 (569,259)
Replacement TFR (for low-mortality countries)	~2.1	Demographic standard
Year UK TFR fell below replacement	1970s	POSTnote 745, citing ONS
Long-term TFR assumption, ONS 2022-based projections	1.45	ONS National Population Projections

The 2023 figure — 1.44 children per woman, lowest on record — is a single year’s snapshot. The longer pattern is more telling. The TFR in England and Wales has been below the replacement level needed to sustain the population without net migration for over half a century. Between 1964 and 2023, the rate of live births per thousand women aged 20-24 fell by 79 per cent.

Where the children went

A sustained sub-replacement fertility rate shifts the population’s age structure older over time. POSTnote 745 cites the ONS projection that the number of people in England and Wales aged 85 and over will be nearly double the mid-2022 figure by mid-2047.

Two adjacent ONS projections from the same 2022-based round complete the picture. The UK population is projected to grow by 4.9 million (7.3 per cent) between mid-2022 and mid-2032, while the projection assumes a similar number of deaths and births over the same window — by implication, the entire 4.9 million increase is projected to come from net migration. Over the full 25-year horizon to mid-2047, the principal projection assumes 1.1 million more deaths than births in the UK; the published zero-net-migration variant — designed to isolate that variable — shows no growth at all.

The Standard Method that sets Kent’s housing-target arithmetic does not adjudicate the policy question of whether sustained net migration is the right response. It accepts the ONS household projection, which is built on the principal projection’s migration assumption, as the input.

Germany as comparator

Germany has had more deaths than births in every calendar year since 1972, according to the Federal Statistical Office (Destatis). 2024 was the 53rd consecutive year of natural population decline; 2025 made it the 54th.

The 2025 figures, provisional at time of publication, give a sense of the current scale. Destatis reports approximately 654,300 live births in 2025 against approximately 1.0 million deaths — a natural-change deficit of around 350,000 in a single year, the largest postwar deficit on the German record.

Germany’s overall population has nonetheless remained stable at over 80 million through this period because of net immigration, particularly the elevated inflows that began in 2015. Destatis’s own analysis is that without that immigration the German population would have begun to fall substantially before now.

The German case is not a forecast for the United Kingdom. It is a documented example of what a sub-replacement fertility rate looks like when sustained over a half-century horizon, and of the policy choice that follows: a country with low and falling births either accepts a smaller population, or sustains it through inward migration. Germany, in practice, chose the second.

What Kent councils actually hold

Within Kent the documentary position mirrors the position at MHCLG. Maidstone Borough Council confirmed in response to a 2025 FOI request that it does not hold five-year local-residency or local-employment data against its adopted Local Plan housing target. Tonbridge & Malling Borough Council confirmed the same in writing. Canterbury City Council returned the same response. Kent County Council, asked the analogous question against its statutory role in the Strategic Housing Market Assessment process, confirmed that it does not hold the data either.

This is consistent with the design of the Standard Method, which does not require councils to disaggregate the figure. It is also consistent with the planning evidence base councils are statutorily required to assemble: a Strategic Housing Market Assessment is required to describe housing need; it is not required to attribute that need between local and inward sources.

The position is therefore that the Standard Method produces a number, the council adopts the number, and neither the council nor the department that set the formula can answer, on the documentary record, what share of the number is locally derived.

What POSTnote 745 records

POSTnote 745 is a 30-page Parliamentary briefing that draws on ONS, OECD and Lords Economic Affairs Committee material. The briefing is, by design, neutral on the policy question of whether sustained net migration is the right response to a sub-replacement fertility rate — it records both sides of that argument. It is not neutral on the demographic fact: the English fertility rate is at its lowest since record-keeping began in 1938, has been below replacement for over fifty years, and the projections built on those facts assume continued net migration as the source of all near-term population growth.

Why this matters for Kent’s water arithmetic

The infrastructure-capacity gap documented in Parts 1 and 2 of this investigation — South East Water’s 32 per cent deliverability ratio against Tonbridge & Malling’s 2040 target, the eleven Kent wastewater treatment works at risk of dry-weather-flow non-compliance, the AMP8 settlement that does not fund the closure of the gap — is downstream of a housing-target arithmetic that the Standard Method produces from inputs the departments and councils do not separately hold.

If the household-formation pressure underlying the target is principally inward — as the ONS migration assumption in the principal projection implies for net population growth — then any policy that materially changes inward migration will materially change the household-formation pressure, and therefore the housing-target arithmetic, and therefore the infrastructure-capacity gap. If the pressure is principally local — births to long-term residents reaching household-formation age — then the demographic outlook (sub-replacement TFR for over fifty years) implies a steadily diminishing source of future pressure.

On the documented record, neither department nor council can say which is the larger contributor in any specific Kent district. The Standard Method does not require them to. The question matters, because it is the question on which the entire infrastructure-capacity argument depends.

Key Takeaways

• MHCLG does not hold data on what share of mandated housing is for residents of the local area (FOI2024/08392, May 2024). Maidstone, Tonbridge & Malling, Canterbury and Kent County Council have confirmed in writing the same absence at local level.

• The Standard Method formula does not distinguish local from inward household formation. It produces an aggregate from ONS household projections and an affordability multiplier; neither department nor council is required to disaggregate the output.

• England and Wales recorded a Total Fertility Rate of 1.44 in 2023 — the lowest on record since 1938 (POSTnote 745, citing ONS). The rate has been below 2.1 replacement for over fifty years.

• The ONS principal projection assumes 1.1 million more deaths than births in the UK between mid-2022 and mid-2047, with all net population growth arising from net migration.

• Germany has had more deaths than births every year since 1972 — fifty-four consecutive years. Its 2025 natural-change deficit was approximately 350,000, the largest postwar deficit on record. Population has remained stable above 80 million only because of sustained net immigration.

What this means for Kent residents

The practical effect is that the housing-target debate within each Kent district has been conducted on numbers whose underlying composition neither central nor local government can publicly account for. A Local Plan adopted under the Standard Method delivers an annual figure to the developable land supply. The share that meets demand from existing residents — children of long-standing Kent families, established workers relocating within the county — versus the share that meets demand from inward migration into the district, is not on the documentary record.

For residents engaging with their council’s Local Plan consultation, the conventional planning question — “is this number proportionate to local need?” — cannot be answered from the council’s own evidence base. The number is the output of a national formula that does not produce that distinction.

For the water-capacity question this investigation has examined, the gap documented in Parts 1 and 2 sits downstream of an arithmetic the responsible authorities cannot fully attribute. Part 4 of this investigation, publishing Monday 1 June, examines the cumulative environmental impact of building to the target the demographic arithmetic has set — across supply, wastewater, chalk-stream ecology, agricultural land and protected-site loss.

Sources

• House of Commons Parliamentary Office of Science and Technology, POSTnote 745, Impacts of birthrate decline, 20 May 2025.
• Office for National Statistics, National population projections: 2022-based, published 2025.
• Office for National Statistics, 2022-based national population projections: Zero net migration variant datasets for Great Britain.
• Ministry of Housing, Communities and Local Government, FOI2024/08392, May 2024 (then DLUHC).
• Maidstone Borough Council, FOI/12883.
• Tonbridge & Malling Borough Council, FOI response, 2025.
• Canterbury City Council, FOI response, 2025.
• Kent County Council, FOI response, 2025.
• Statistisches Bundesamt (Destatis), Live births and deaths (time series), Federal Statistical Office of Germany, 2025 provisional figures.
• Kent Local News Water Investigation Part 1 (Edition A, 4 May 2026; Edition B, 7 May 2026; posts 19222 + 19223).
• Kent Local News Water Investigation Part 2 (11 May 2026; post 20345).