Money & government · Untapped revenue

Raising revenue without raising headline rates: what's actually on the table

Proposals for raising more revenue without increasing headline tax rates, each shown with its theoretical value, what is plausibly collectible, and who has estimated it. These are contested policy options, not money sitting uncollected.

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All figures in £bn per year · Sources cited inline · Last updated Jun 2026

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Section 1: The Cost Stack

What politicians and media focus on

Asylum seeker processing

Includes accommodation, case processing, legal aid and admin costs for asylum seekers awaiting decisions.

Source: Home Office 2023–24

£4bn

per year

Benefits for asylum seekers

Asylum Support cash payments and additional welfare costs while claims are decided.

Source: Home Office / DWP 2023–24

£1.5bn

per year

Total annual cost

Immigration system costs

~£5.5bn

This is the number that generates thousands of newspaper headlines per year. It is real — but it is tiny compared to what is being left on the table.

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Section 2: The Revenue Opportunity Stack

What politicians and media largely ignore

Reduce the Corporation Tax gap

HMRC estimates the TOTAL tax gap at £59.2bn for 2024-25 (6.4% of tax due), of which Corporation Tax is about 35%, or roughly £21bn. The tax gap is a theoretical estimate of tax not collected — it is not a sum that could be recovered in full by any known enforcement programme, and actual compliance yield is a fraction of it.

Source: HMRC, Measuring tax gaps 2026 edition (2024-25 estimates)

£21bn

per year

Wealth tax on £10m+ assets

2% annual tax on net assets above £10m affecting ~22,000 individuals. Estimates range from £10bn to £24bn depending on behavioural responses. Mid-point used here.

Source: LSE Wealth Tax Commission / IPPR / Warwick University

£17bn

per year

Big tech fair taxation

Large US tech multinationals are widely reported to declare minimal UK profits relative to their UK user base and revenue, via transfer pricing structures. Closing this gap is estimated to raise an additional £2–4bn/yr, though the modelling assumptions behind that estimate are not independently sourced here. (A previously-shown "£100bn+ in UK economic activity" figure for named companies has been removed — no source could be found to support it.)

Source: HMRC / Tax Justice UK / FT analysis

£3bn

per year

Water company profit reclaim

Water company shareholders received £2.4bn in dividends in 2022–23 while companies accrued £64bn in debt. Nationalisation would redirect this to infrastructure instead.

Source: Ofwat / Water UK Annual Reports 2023

£2.4bn

per year

Rail profit reclaim

Franchise operators extracted ~£500m/yr in profit before the COVID-era Emergency Recovery Measures Agreements. Now being repatriated under Labour's rail nationalisation.

Source: ORR / DfT 2023

£0.5bn

per year

Energy windfall tax (sustained)

North Sea oil and gas operators made £11.6bn profit in 2022–23. A sustained windfall tax at proper rates (not the scheduled phase-out) could raise £5–10bn/yr. Mid-point used.

Source: OBR / DESNZ 2023–24

£7.5bn

per year

Total annual opportunity

If all these streams were collected

~£51.4bn

These estimates come from HMRC, OBR, the LSE Wealth Tax Commission and corporate filings, but they are not equivalent and should not be added together as though they were: they mix theoretical gaps with modelled yields, cover different years, and several assume behavioural responses that are themselves disputed. Treat the total as an upper bound on a set of contested proposals, not as available revenue.

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A different kind of war chest: pension re-investment

A stock of capital that could be redirected, not a flow of new revenue — kept separate from the £bn/yr stack above

Of the £207.7bn in assets that 25 of 28 UK master trusts disclosed for their 2026 asset-allocation report, only 15.5% sits in UK investment of any kind, against 84.5% overseas (The Pensions Regulator). The voluntary 2023 Mansion House Compact asked funds to invest 5% in unlisted UK assets specifically.

Illustrative unlock, one-off

If UK pension funds redirected more toward domestic assets

£50–80bn

This site’s own illustrative figure, not a published official estimate — see /pensions and /swot for the full workings and caveats.

Affordability and likelihood, honestly stated

Unlike the tax measures above, this “war chest” is not the government’s money to spend — it is privately held pension capital, and redirecting it is a matter of regulation or incentive, not a budget line. The Mansion House Compact is voluntary and has not hit its own target; a regulatory mandate or a significant tax incentive would be needed to unlock the range above, and both are politically contested. Likelihood without a policy change: low. With one: genuinely uncertain, and not costed here.

The Scale Comparison

Revenue opportunity vs the cost of the asylum system

Total asylum cost

£5.5bn

Corporation Tax gap (theoretical)

~£21bn

All opportunities combined

~£77bn

Not to perfectly proportional scale — representative comparison only

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Section 3: What Could It Fund?

The opportunity cost of under-taxing wealth and corporations

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Reduce the ~£21bn Corporation Tax gap

Source: HMRC Tax Gap 2023–24

Could fund:

✓Fund the entire NHS revenue budget supplement (~30% increase)
✓Train and employ 47,000 additional nurses for 10 years
✓Build 156,000 social homes every year
✓Eliminate all NHS waiting lists within 2 years

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Implement the £17bn wealth tax alone

Source: LSE / IPPR

Could fund:

✓Fund free university tuition for all UK students (~£9bn/yr)
✓Double the social care budget (+£7bn/yr)
✓Provide £1,000 "baby bond" to every newborn for 60 years
✓Fund the entire defence budget increase (2.5% GDP target)

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Collect £3bn more from big tech

Source: HMRC / FT

Could fund:

✓Fund the entire asylum processing system twice over
✓Recruit 10,000 additional GPs
✓End rough sleeping homelessness with funding to spare

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Section 4: The Pareto Point

"1% of media and political energy goes on corporate tax enforcement. 99% goes on immigration. The fiscal return is exactly backwards."

Immigration debate

99% of energy

Fiscal return:

−£5.5bn/yr

(cost of system, not counted against economic contribution of migrants)

Corporate tax enforcement

1% of energy

Fiscal opportunity:

£59.2bn/yr theoretical

HMRC total tax gap, 2024-25. A theoretical estimate of tax not collected — not revenue available to spend.

The maths:

These figures cannot simply be added together or treated as available revenue. The tax gap is a theoretical estimate of tax not collected, not a pot that can be recovered in full: HMRC's actual additional compliance yield runs at a small fraction of the gap, and the remainder reflects insolvency, error, disputes and activity no enforcement regime has been shown to recover. Wealth-tax estimates are academic scenarios with wide ranges and assume behavioural responses that are themselves contested. Read each line as a separate, uncertain proposal — not as a single sum waiting to be collected.

Sources & Methodology

• HMRC, Measuring tax gaps 2026 edition (published 23 June 2026): total tax gap £59.2bn (6.4%) for 2024-25; Corporation Tax about 35% of it. The 2023-24 estimate was revised up from £46.8bn to £52.8bn.

• LSE Wealth Tax Commission (2020): Wealth tax on £10m+ at 2% raises £10–24bn/yr

• IPPR, Warwick University (2022–23): Corroborating wealth tax estimates

• Ofwat / Water UK Annual Reports 2023: Water sector dividends £2.4bn despite £64bn debt

• OBR / DESNZ Energy Profits Levy analysis 2023–24: North Sea profits, levy revenue projections

• HMRC / Home Office Immigration Statistics 2023–24: Asylum costs £4bn processing + £1.5bn support

• OBR Fiscal Sustainability Report 2024: Net fiscal contribution of immigration strongly positive

This page presents analysis based on published data. It does not advocate for specific policies. All revenue estimates involve uncertainty and behavioural responses. Sources are linked from each data point description above.