UK Migration — A Briefing for the Green Party
One of nine party briefings, written from inside the Green Party's worldview to make the strongest version of their case on migration. Where the evidence reinforces; where it requires sharpening; the political coalition; three things to do in the next twelve months.
Migration and Benefits Policy — Evidence and Direction
For: Green Party leadership and policy team Date: May 2026 Premise: This briefing is written from inside the Green Party worldview as articulated by Zack Polanski since September 2025. It uses the available data to reinforce, sharpen, and stress-test the Green migration framework. It does not advocate the positions of other parties.
1. The position you hold
The Green Party of England and Wales has tripled its membership since Zack Polanski's leadership election. At the May 2026 local elections you won 586 seats; some polls now place you ahead of both Labour and Conservatives. The published Migration Policy framework is among the most detailed of any party: aspirational world without borders; managed humane migration in the interim; migrants treated as citizens-in-waiting; visitor visas for any arrival; full benefit, NHS, and student finance access for settled status holders on equal terms with British citizens; automatic British citizenship for all UK-born children; commitment to tackling statelessness; regularisation pathways for undocumented migrants without penalty; end of detention except in narrow circumstances.
The political role you play is significant beyond your seat count: you hold the values position that other parties would also hold if the political incentives allowed. With Labour under pressure from Reform on the right, the Green presence on the left is what prevents Labour from drifting further from the values base that won it 2024. The integrationist-pro-migration position is no longer comfortably within Labour; it is now substantially carried by you.
2. Where the evidence reinforces the Green direction
Hostile environment costs more than it saves. The 2022 LSE CASE Report 140 (Benton et al.) modelled the inverse — the cost of removing No Recourse to Public Funds. For 362,000 households (including 106,000 with children), lifting NRPF for vulnerable groups produced 10-year present value gains of £2.6bn against costs of £1.7bn — a net positive of £872m. Lifting for all affected groups produced £3.2bn gains against £2.8bn costs — net positive £428m. The implication: the hostile environment generates marginal central government saving against substantial cost-shifting to local authorities and substantial human cost.
The NRPF Connect 2024-25 data shows £93.7m local authority NRPF spend across 5,724 households, concentrated in Greater London (£51.4m, 2,799 households). This is the cost-shift the LSE work measured. Your position to dismantle the hostile environment has fiscal backing once the cost-shift is properly counted.
Refugee employment improves with status security. Refugee employment rates are 26.5% on UC, 56% of working-age asylum arrivals overall — substantially below 75% UK-born. Status insecurity is one of the major causes; employers are reluctant to hire someone whose status may be revoked. Labour's 30-month review cycle implemented from March 2026 makes this worse, not better. Your position to revert to a stable settlement pathway has direct employment and contribution effects.
Climate displacement is a real and growing category. No other major UK party explicitly recognises climate-induced displacement as a category requiring UK reception responsibility. The empirical literature on climate migration is well-developed; the World Bank, IDMC, and IOM all project rising displacement through the 2030s and 2040s. Your framework uniquely engages with this; the others either ignore it or treat it as a future problem.
Universal access to children's services has overwhelming evidence. Education Act 1996, ECHR Protocol 1 Article 2, UN Convention on the Rights of the Child Article 28. The evidence on the long-term costs of denying schooling or healthcare to children — even based on parental immigration status — is unambiguous. Your position is unambiguously aligned with the evidence; the Conservative and Reform positions on schools and NHS access restriction are not deliverable for legal and public-health reasons.
Voluntary returns at the cost differential. Voluntary returns at £4,300/person versus enforced at £48,800/person. The Green framework's emphasis on humane facilitation of return aligns with the cost-efficient mechanism. The Conservative-Reform mass-deportation framing is fiscally inefficient before its other costs are counted.
Migration is economically positive on aggregate. OBR average migrant tax contribution £19,500/year. Combined annual immigration revenue from fees, IHS, and Skills Charge: £4.1 billion. Lifetime contribution at age 25 on average wage: +£500,000 (OBR) — higher than UK-born average worker (+£250,000) because the UK has not paid for migrants' childhood education. Your framing of migration as economically and morally positive is supported by the macro evidence.
3. Where the evidence requires sharpening
The fiscal implications of full equal-access settlement need acknowledgement. The Green policy MG601 ("Residents with settled status have the same access to benefits, student finance, and the NHS as British Citizens") plus expedited regularisation creates a substantially larger benefit-eligible population than current. The MAC modelling shows mixed lifetime fiscal contribution by route — Skilled Worker positive, Family route negative, Health & Care dependants negative. Expanding access without contribution conditions produces net fiscal cost in the short and medium term.
The Green response to this is essentially that fiscal-balance is the wrong frame: migration is a humanitarian and economic-justice question, not a fiscal optimisation problem. This is a coherent values position. But it does not engage the fiscal data on the data's own terms, and that creates a vulnerability when opponents present the fiscal case.
The recommended adjustment: own the fiscal cost openly. Frame it as the cost of a decent country. Pair it with offsetting revenue commitments (wealth tax, corporation tax adjustments, environmental taxation) that the Green economic programme already proposes. The fiscal arithmetic does not need to be hidden if the values argument is being made directly.
Climate displacement scale needs framing. Including climate-induced displacement as a category for UK reception is right-aligned with the evidence. But the volume implications — climate displacement projections run to hundreds of millions globally over the next two decades — need to be framed in terms of what UK responsibility looks like proportionally.
The recommended approach: anchor UK climate-displacement reception in (a) historical-emissions responsibility (UK contribution to cumulative emissions); (b) per-capita-GDP capacity; (c) coordination with comparable states. This gives a defensible scale framework rather than open-ended reception.
Regularisation pathway design. Your policy commits to free advice and support for undocumented migrants to regularise without penalty. The volume estimates for the irregular population — Pew 700,000-900,000; GLA 594,000-745,000; Birmingham 594,000-745,000 — give a realistic scale. The recommended approach: phased regularisation by length of UK residence (e.g. 10-year residents first, then 5-year, then current arrivals), with clear criteria. This is operationally credible at the scale the data suggests.
The Spanish, Italian, and Portuguese regularisation programmes provide international precedent. The fiscal evidence on regularisation is broadly positive — IPPR's pre-2010 modelling and subsequent work suggest regularisation produces net fiscal gain over time as people enter the formal economy. This evidence supports the Green direction; cite it.
Detention reduction scope. Your policy ends detention except for serious crime and national security. This is operationally credible — current detention is 2,200 places against 22,996 annual intake; most detention is short-term and procedural, and most leavers (51%) are released on bail rather than removed. The detention infrastructure largely operates as a cost without producing the removals it was designed for. The Green position is fiscally rational on the data.
4. Where the evidence supports the Green argument against other parties
Reform's £14.3 billion fiscal claim is not credible. Reform's proposed asylum review and ILR rescission package is presented as saving £14.3bn over a Parliament and £137bn over its lifetime. The model behind these figures is not published. The MAC December 2025 modelling shows Skilled Worker main applicants at +£689,000 lifetime per person; rescinding ILR removes contributors as well as costs. Reform's proposal to detain and process for review the cohort of recent asylum grants is not deliverable at current detention capacity (2,200 places).
The Green response: present the MAC data and ask Reform to publish their model. The fiscal arithmetic, when made transparent, does not support the Reform claim.
Conservative ECHR withdrawal cascade is unmodelled. Belfast/Good Friday Agreement implications, UK-EU TCA cooperation termination, extradition disruption, business confidence effects. None has been costed in any Conservative document. The Green response: demand independent costing before any party can credibly take ECHR withdrawal to a manifesto.
Labour's 30-month refugee cycle is not fiscally rational. Once the offset costs (administrative cost of repeat reviews, reduced refugee employment from status insecurity, reduced refugee long-term investment in UK) are counted, the policy is approximately fiscally neutral and produces clear human costs. The Green response: revert to 5-year-then-ILR refugee pathway, defend as fiscally rational once offset costs are counted.
5. The political coalition
The Green pro-migration position has historically been a minority position in UK politics. The 2026 polling shift suggests this may be changing. The combination of Labour's drift toward Reform-lite positioning and the broader cultural reaction to maximum-restriction framing has created space for a clearly differentiated pro-migration position.
The political coalition includes: progressive voters previously voting Labour now feeling the party has moved away from them; younger voters (Greens have the youngest voter base of any party); urban professional voters in cities with high migrant populations who see the human and economic effects directly; and some traditional left-wing voters who hold the values position even as their economic position is precarious.
The risk for the Green Party is that the position becomes seen as elite-disconnected from working-class economic concerns about housing, services, and wages. The recommended response is to link migration framing directly to the economic-justice programme: housing investment, public service investment, fair wage frameworks. The Green position is that scarcity of housing, services, and decent wages is a political choice — not a consequence of migration. Make this argument explicitly.
6. Three things to do in the next twelve months
1. Publish a costed regularisation programme. Phased by length of UK residence; clear criteria; integration support funded. Cite the international precedents (Spain, Italy, Portugal) and the fiscal evidence (positive net effect over 5-10 years). This makes the Green undocumented-migrant position concrete and deliverable rather than aspirational.
2. Cost the integration investment commitment explicitly. £25-30 billion per year sustained for English language training, employment programmes, dispersal coordination, and refugee resettlement support. Pair with the Green wealth-tax and corporation-tax framework. This is the missing piece in the Green policy framework that other parties exploit; supply it.
3. Build the climate displacement framework. Historical emissions responsibility metric, per-capita capacity metric, coordination framework with comparable states. Specify what UK climate displacement reception looks like — both numbers and routes. This is your unique policy area; develop it with the rigour the issue deserves.
These three together address the Green policy framework's weakest analytical points, give the position concrete deliverables, and develop the unique policy area (climate displacement) that no other party occupies.
Costed implications: short summary
This block summarises the headline costed assessment of this party's stated platform. The full breakdown — proposal-by-proposal cost ranges, savings, behavioural responses, deliverability constraints, and legal exposure — is in the costed cross-party companion (~10,000 words, all 9 parties).
| Dimension | Assessment |
|---|---|
| Net fiscal effect (annual) | -£1.0bn to +£2.7bn/yr (assumption-sensitive) |
| Confidence | LOW |
| Legal exposure | MEDIUM |
| Deliverability | LOW (parliamentary reach limited) |
Top 3 upsides (analytical)
- Most internally coherent values-based package; honours human-rights commitments
- Regularisation of undocumented migrants has genuine evidence base (Spanish 2005, Italian 2003) for substantial fiscal-positive effect over 5-10 years
- Detention end is fiscally and morally efficient; equal access on benefits compounds long-term integration outcomes
Top 3 downsides (analytical)
- Visitor visa universal access creates substantial population-pressure response outside developed-state norms
- Equal benefit access (£0.6-2.5bn/yr cost) may be politically vulnerable to 'welfare magnet' framing
- Net fiscal effect highly sensitive to behavioural-response assumptions; under unfavourable assumptions, package is net negative
Note on this assessment
This costed assessment is written from outside the party's worldview, using the same evidence base. It complements (does not replace) the within-worldview analysis in this briefing. The full companion document gives proposal-by-proposal cost ranges with confidence labels and is best read alongside this briefing.
For comparable cross-party assessment, see the comparative summary table at the end of the companion document.