UK Migration — A Briefing for the Conservatives

One of nine party briefings, written from inside the Conservatives' worldview to make the strongest version of their case on migration after the 2022-2024 surge. 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: Conservative leadership and Shadow Home Office team Date: May 2026 Premise: This briefing is written from inside the Conservative worldview as articulated by Kemi Badenoch since November 2024. It uses the available data to reinforce, sharpen, and stress-test the Borders Plan and associated positions. It does not advocate the positions of other parties.

1. The position you hold

The Borders Plan announced by Kemi Badenoch from October 2025 onwards represents the sharpest break with previous Conservative migration policy in a generation. The package includes: total ban on asylum claims for new illegal entrants; ECHR withdrawal, ECAT withdrawal, and Human Rights Act repeal; a Removals Force with 150,000 annual deportation target; deportation of foreign criminals; end of Immigration Tribunal, Judicial Review, and legal aid for immigration cases; numerical cap on legal migration; and ILR qualifying period extension from 5 to 10 years.

The political logic is to recover voters lost to Reform UK while differentiating on deliverability and seriousness. Badenoch's framing — "tough but deliverable" against Reform's "tough and we mean it" — is the wedge.

You face a structural problem the data confirms: the immigration system you inherited from your own party's previous governments is the one that produced the 2022-2024 net migration peak. The "Boriswave" cohorts begin reaching ILR eligibility in 2026 under previous rules. The evidence base shows that this cohort's lifetime fiscal contribution varies sharply by route — Skilled Worker main applicants strongly positive, Family route negative — and the political pressure is to address this without acknowledging the responsibility of the previous Conservative governments that allowed it.

2. Where the evidence reinforces the Borders Plan direction

ILR qualifying period extension. Your February 2025 announcement (5 to 10 years) predates Labour's similar policy. The MAC December 2025 data supports the route-sensitive case. Skilled Worker main applicants (excluding Health & Care) +£689,000 lifetime; Family partner route -£109,000. Extending the qualifying period delays full benefit access for the affected cohort and generates additional visa renewal fees and IHS revenue across the longer period. Home Office published behavioural assumption: 10-20% reduction in affected inflows.

The CPS analysis (Here to Stay?, September 2025) is your strongest external evidence. Karl Williams' work for CPS, using HMRC PAYE data, suggests that the LFS-based fiscal modelling overstates earnings for some recent cohorts, particularly Indian and Nigerian nationals aged 22-40. CPS argues this means OBR's lifetime projections are too optimistic. The argument is contested (Portes himself, whose data CPS cites, has not drawn the same inference) but it is academically defensible.

Asylum cost control framing. The NAO May 2025 briefing on asylum accommodation contracts is decisive: original £4.5 billion estimate now expected to reach £15.3 billion. Hotels at £170/person/day vs dispersal at £27/day. The three suppliers reported total profit of £383 million across the AASC contracts between September 2019 and August 2024, with an average reported margin of 7%. This is a procurement failure that crosses party lines. You can pursue this aggressively without the legal exposure that accompanies your other policies. Open-book contracting, profit caps, and aggressive renegotiation are deliverable through executive procurement powers without primary legislation.

Returns volume increase. Returns in the year ending December 2025 totalled ~38,000 across separate categories: 9,914 enforced; 28,004 voluntary (10,260 assisted within); 18,279 port; 5,634 FNO. The 11x cost differential between enforced (£48,800/person) and voluntary (£4,300/person) returns is decisive: any incremental return capacity should go into voluntary first. Your 150,000/year target requires either substantial voluntary expansion or major enforced-returns infrastructure investment. The voluntary route is more cost-efficient and faces lower legal exposure.

Foreign National Offender removals. FNO returns are at their highest level since 2018. This is a high-political-salience area where the evidence supports the position — these are people whose criminal conduct provides clear grounds for removal. The Rochdale grooming gang Article 8 cases that Badenoch cites are a genuine policy failure that the data supports challenging.

3. Where the evidence requires sharpening or revision

The 150,000/year deportation target is not currently deliverable. Detention capacity is 2,200 places. Annual detention intake is 22,996. Of detention leavers, 51% are released on bail rather than removed — meaning the binding constraint is removability (whether destinations will accept returns), not detention capacity. Adding capacity does not solve a removability problem. The high-volume source countries without functional returns agreements (Iran, Eritrea, Afghanistan, Sudan, Syria) are mostly states the UK cannot negotiate with directly because they are sanctioned, hostile, or in active conflict.

To make 150,000/year credible, you need either:

• Massive voluntary returns expansion (achievable at the cost differential)
• Third-country processing arrangements (Rwanda failed; nothing has replaced it; the IPPR modelling suggested £200,000/person at scale)
• New bilateral agreements with destination countries — visa-sanction leverage works on some (the Pakistan agreement is a model) but not on the largest sources

The Borders Plan as currently framed does not specify which mechanism delivers the 150,000. This is a credibility gap that opponents will exploit.

ECHR withdrawal cascade costs are unmodelled. Your March 2026 statement endorsed withdrawal but you have not published costing of the consequences. Belfast/Good Friday Agreement implications. UK-EU Trade and Cooperation Agreement law-enforcement and judicial-cooperation termination grounds. Extradition treaty effects with non-EU states. Business confidence. These are cascade costs that need their own analysis before withdrawal can be presented as net positive.

The Institute for Government and others have raised these. The Conservative position should commission independent costing — your own ECHR Commission could do this work — before the policy is taken to a manifesto. The risk of presenting withdrawal without this analysis is that opponents (including the Lib Dems and parts of business) will fill the analytical vacuum with their own numbers.

The Removals Force budget (£1.6 billion) is not aligned with the target. At enforced-returns unit cost of £48,800, £1.6 billion delivers approximately 33,000 returns — a fifth of the 150,000 target. To deliver 150,000 enforced returns at current unit costs requires £7.3 billion. To deliver 150,000 mostly-voluntary returns at the 11x cost advantage requires approximately £650 million — substantially less. Either revise the target or revise the budget.

The "Boriswave" framing creates a vulnerability. You are arguing that ILR rules need extension because the previous Conservative governments allowed too much migration. This is fair, but it requires explicit accounting of which Conservative governments made which decisions. Without this, the framing produces the question "why should voters trust the Conservatives now if you didn't deliver before?" The answer needs to be substantive — Badenoch's leadership change, learning from delivery failures, specific commitments to evidence-led design.

4. Where the evidence suggests caution on cultural framing

The March 2026 Jewish News interview connecting immigration restriction to antisemitism ("people are coming in from places with a culture of antisemitism") is politically salient but analytically problematic.

The Census 2021 data does not support precise religion-and-cohesion claims. Religion is not collected in welfare or tax administrative data. Asylum claimants from a given country are often disproportionately religious minorities within that country (Christians from Iran, Ahmadis from Pakistan, Hazaras from Afghanistan). Country-of-origin religion proportions do not represent the religious composition of asylum cohorts.

This matters because:

• The framing creates analytical vulnerabilities opponents will exploit (presenting countervailing data)
• It risks alienating Conservative-leaning voters in religiously diverse communities
• It overlaps with framing used by Restore Britain in ways the Conservative Party has clear reasons to keep distance from

The recommended adjustment is to anchor the migration-and-cohesion argument in route, contribution, and integration evidence rather than in country-of-origin cultural assertion. The MAC route data and the integration evidence (Danish model, Cantle, Goodhart) provide more analytical ground without the cultural-essentialist exposure.

5. Where the evidence suggests a stronger flank against Reform

Reform's positions create three specific opportunities for Conservative differentiation that the data supports:

Reform's £14.3 billion fiscal claim is not credible. The MAC modelling shows Skilled Worker main applicants at +£689,000 lifetime per person. Reform's policy of rescinding ILR and replacing with £60,000-threshold visas removes contributors as well as costs. Reform has not published a model behind the £14.3bn figure. Conservative challenge: "Show us the numbers." This positions the Conservative Party as the serious deliverer and Reform as the populist promiser.

Reform's retrospective ILR restriction breaks vested rights. This is a clear differentiator. Badenoch's position is prospective extension; Reform's is retrospective rescission. The legal exposure (Article 1 of Protocol 1, Article 14, Article 8) is dramatically higher for retrospective restriction. This is the single most defensible Conservative criticism of Reform from a rule-of-law perspective.

Reform's asylum review proposal is not deliverable. Reviewing five years of granted asylum claims requires capacity Reform has not specified. The detention infrastructure does not exist. The legal process for revocation is contested. Conservative challenge: "How do you actually do this?" — and propose your own narrower, deliverable alternative (FNO removal, deportation of post-grant criminal offenders, end of asylum claims for new illegal arrivals).

The differentiation strategy is not "less restrictive" but "more deliverable." This is consistent with Conservative messaging on competence and consistent with what the evidence base supports.

6. Three things to do in the next twelve months

1. Commission and publish ECHR-withdrawal cascade costing. Your own ECHR Commission has the standing to do this. Independent cost analysis of Belfast/Good Friday implications, TCA cooperation, extradition, business confidence. Publish before manifesto. Without this, the policy is exposed.

2. Sharpen the Removals Force on voluntary returns. Reframe target as "scaling enforced and voluntary returns" rather than "150,000 deportations." Use the 11x cost advantage to argue more deliverable, more cost-efficient. Specify which destination agreements you would prioritise.

3. Anchor the Conservative position in MAC route data. This is your strongest analytical ground. Skilled Worker positive, Family route negative — the case for differentiated treatment is straightforward. Adopt the MAC framework as the Conservative evidence baseline. This positions you against Reform's lack of analytical basis and against Labour's failure to fully exploit its own evidence work.

These three together address the Borders Plan's weakest analytical points, sharpen differentiation against Reform, and lock in evidence-led credibility for the run-up to the next election.

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)	-£10 to -£20bn/yr in operation period
Confidence	LOW-MEDIUM
Legal exposure	HIGH
Deliverability	LOW (capacity gaps)

Top 3 upsides (analytical)

• Symbolically responsive to mandate-deficit dynamics (Conservative voters did not get the migration reduction promised)
• ILR period extension specifically addresses the Boriswave cohort the previous government created
• Sharp differentiation from Labour and (on deliverability) from Reform

Top 3 downsides (analytical)

• Detention scale-up (~25× current capacity) plus £8-20bn one-off; £15-30bn/yr operational at full target — deliverability gap is the central problem
• ECHR withdrawal cascades through Belfast Agreement, TCA, Refugee Convention; legal exposure across multiple frameworks
• Conservatives positioned as authors of the problem AND the cure — credibility cost is substantial

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.