Britain today · Immigration

What does immigration contribute to the UK?

What the official numbers show, what official modelling suggests would change, and what nobody can honestly calculate.

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How to read this page

Immigration is argued about with numbers that measure different things. This page separates them into three kinds of evidence and labels every figure with which kind it is.

  • Official observed statisticMeasured and published by an official body. Describes what is, not what would happen.
  • Official modelled scenarioPublished official modelling of a hypothetical change. A scenario, not a forecast.
  • Unknown — not supported by official evidenceNo official UK data supports a reliable number. Stated as unknown rather than estimated.

This page takes no position on whether immigration should rise or fall. That is a political judgement, and the numbers here do not settle it — they only make clear what is actually known.

First, two things the numbers are not

Net migration is not immigration

Net migration is arrivals minus departures. The 171,000 baseline is the gap between about 813,000 people arriving and 642,000 leaving in the year ending December 2025 (provisional). Cutting net migration to zero would not mean nobody arrives — it would mean arrivals and departures balance. See both measures charted →

Lower future migration ≠ fewer people here now

The slider changes a future flow. It does not remove a single person already living or working in the UK. That is why the NHS, employment and housing figures below stay fixed when you move it: they measure what the country currently relies on, not a quantity that shrinks with the setting.

Official modelled scenario

If net migration were lower, what does official modelling say happens?

Drag the slider to cut annual net migration from the current baseline of 171,000 towards zero. The four figures below are the only outcomes on this page that move, because they are the only ones an official body has modelled.

0a year (0% of the baseline)
No changeNet migration zero

Net migration would be 171,000 a year instead of 171,000. That means fewer people arriving than would otherwise — it does not remove anyone already living or working in the UK, and at zero it does not mean nobody arrives, only that arrivals and departures balance.

Tax migrants pay in, 2028/29

£0.0bn

The extra tax migrants pay — income tax, National Insurance, VAT, and visa and NHS surcharge fees.

Cost of services for them, 2028/29

£0.0bn

What it costs to keep the NHS, schools and other services running at the same standard per person — migrants tend to be younger, so this costs less per head.

Extra government borrowing, 2028/29

£0.0bn

Tax coming in falls by more than costs go down, so the government has to borrow more to cover the gap, per the OBR's figures.

Effect on national debt, 2028/29

0.00 pp

How much bigger the national debt gets as a share of the economy, compared to the OBR's March 2024 main forecast.

Illustrative OBR-based scenario — not an official forecast for this slider setting. The OBR modelled one case: net migration 200,000 a year higher than its central forecast, giving +£18.0bn receipts, +£6.1bn in public-service requirements, −£13.1bn borrowing and −2.5 percentage points of debt by 2028/29. The figures above scale that single result to your setting and reverse the sign. The OBR published no results for intermediate values, and the real relationship need not be proportional. OBR, Economic and fiscal outlook, March 2024 — Box 4.5, "The impact of migration on the fiscal forecast" · Published March 2024.

What migration currently contributes

These are measured statistics, not projections. They describe the country as it is today — the reliance that already exists — and none of them changes when you move the slider.

Housing: what the evidence actually shows

Housing is where claims and evidence diverge most sharply, so it is worth being precise. The pressure migration places on housing is real, but it falls overwhelmingly on the private rented sector — not, as is often assumed, on social housing.

  • Official observed statistic

    Marginally lower

    Foreign-born residents’ likelihood of living in social housing vs UK-born

    At the 2021 Census, foreign-born residents in England and Wales were marginally LESS likely than UK-born residents to live in social housing. Social renting was broadly stable across all country-of-birth groups between 2011 and 2021.

    Migration Observatory, Migrants and Housing in the UK, using Census 2021 · Census 2021 (England and Wales)

  • Official observed statistic

    17%

    Recent arrivals (within five years) who own their home

    The great majority of recent migrants rent privately rather than socially. Tenure converges towards the UK-born pattern the longer people stay.

    Migration Observatory, Migrants and Housing in the UK, using Census 2021 and UKHLS · Census 2021 / UKHLS 2021–22

  • Official observed statistic

    Not eligible

    Most work, study and family visa holders, for social housing

    Visas are generally issued with a No Recourse to Public Funds condition, which bars an allocation of social housing and housing-related benefits. Someone on such a visa cannot join the waiting list at all, so their arrival does not add to social-housing demand in the way it adds to private-rental demand.

    GOV.UK, Public funds guidance for people subject to immigration control · Current guidance

Unknown — not supported by official evidence

What we cannot honestly calculate

These questions get confident numerical answers in public debate. Official UK data does not support any of them, and inventing a figure would be worse than leaving the gap visible.

How would reducing immigration change crime?
No official UK data supports an estimate. Foreign-national prisoner counts cannot be turned into a crime rate: the denominator (the foreign-national population, including short-term visitors) is not measured on a comparable basis, the prison population reflects sentence length and remand as much as offending, and nationality at conviction says nothing about immigration status or route of entry. Any figure produced this way is an artefact of the method, not a finding.
How many GP appointments would be freed up?
There is no official model linking a change in net migration to appointment availability. Migrants are both users and providers of health services — the same change affects demand and staffing simultaneously, in different places, over different timescales. Published data does not allow those to be separated.
How many social homes would be released?
No official estimate exists, and the mechanism usually assumed does not hold: most recent visa holders are barred from social housing by the No Recourse to Public Funds condition, so reducing those visas releases no social housing at all. Effects on the private rental market are real but are not quantified in any official model.
What happens to NHS staffing if migration falls?
The OBR scenario models fiscal aggregates, not workforce composition. No official source establishes a proportional relationship between a change in annual net migration and a change in NHS headcount — recruitment depends on visa policy for specific occupations, domestic training pipelines, pay and retention, none of which move mechanically with a net migration total.

Methodology, assumptions and limits

Net migration is not immigration
The slider changes NET migration — arrivals minus departures. The baseline of 171,000 is the difference between roughly 813,000 arrivals and 642,000 departures in the year to December 2025. Net migration of zero does not mean nobody arrives; it means arrivals and departures balance.
This models future flows, not people already here
Reducing future net migration does not remove anyone currently living or working in the UK. The NHS staff, payrolled workers and households shown on this page stay exactly where they are. That is why those figures do not move when the slider moves — they describe current reliance, not a quantity that shrinks with the setting.
Stocks versus flows
Net migration is a flow (people per year). NHS workforce, payrolled employments and housing tenure are stocks (people at a point in time). Applying a percentage change in a flow to a stock is one of the most common errors in this debate, and this tool is built specifically not to do it.
Why the fiscal figures are interpolated
The OBR published one scenario: net migration 200,000 per year higher than its central forecast, with effects stated for 2028/29. This tool scales that result linearly to the reduction you choose and reverses the sign. The OBR did not publish results for intermediate values, and the true relationship need not be proportional — larger reductions could plausibly have more than proportional effects. Treat the outputs as an illustration of direction and rough magnitude only.
Forecast vintage
The OBR scenario comes from the March 2024 Economic and fiscal outlook and is anchored to that forecast, that policy environment and that migrant composition. It has not been re-run against the lower migration levels since observed. It remains the most directly relevant published official model, which is why it is used here, but it is not current.
Different geographies
These figures do not all cover the same territory. NHS workforce figures are England only. Census tenure figures are England and Wales. Payrolled employment, migration and fiscal figures are UK-wide. GMC and NMC registers are UK-wide but count licence-holders, not people in NHS posts.
Nationality, birthplace and status are three different things
A person can be a British national born abroad, a non-British national born here, or a foreign national with indefinite leave to remain. Sources on this page measure whichever of the three their own collection uses, and each figure says which. They cannot be added together or treated as interchangeable.
Rounding and uncertainty
Migration estimates are provisional and routinely revised — the 2024 net migration figure was revised from around 600,000 to 331,000 as ONS changed method. Fiscal scenario outputs are stated to one decimal place for readability, which implies far more precision than the underlying modelling carries.