PolicyLens

Liberal Democrats - Tax

Reform capital gains tax

Reform CGT rates and reliefs while adding allowances for inflation and small businesses.

Last updated: May 2026.

Read the policy-specific methodology note

Policy baseline

Party costings claim GBP 5.21bn by 2028-29 from CGT reform. Behavioural lock-in and relief design justify a lower central case.

  • Applies to taxable capital gains.
  • Inflation allowance reduces some liability.
  • Timing and avoidance responses are large.

Core trade-offs

The direct beneficiaries are the exchequer and perceived tax fairness. The costs fall mainly on asset owners and some entrepreneurs. The main economic question is lock-in can reduce receipts and investment.

  • The exchequer and perceived tax fairness gain most directly.
  • Costs fall mainly on asset owners and some entrepreneurs.
  • Key risk: lock-in can reduce receipts and investment.

Fiscal impact by 2028-29

-GBP 7.0bn to -GBP 1.0bn. Central estimate: -GBP 4.0bn.

  • Positive numbers mean net fiscal cost; negative numbers mean Exchequer savings.
  • Main channel is the scored tax, spending or delivery change.
  • Offsets depend on tax receipts, behaviour and pass-through.
  • Range reflects uncertain implementation and economic response.
  • This is not an official costing.

Economic impact by 2028-29

  • Jobs: Little direct job effect; sector-specific taxes can reduce hiring in affected industries.
  • Wages: Legal taxpayers may shift costs to workers, owners or consumers over time.
  • Prices: Some pass-through likely where market power or fixed demand exists.
  • GDP / productivity: Usually mildly negative before spending use; stronger if investment or mobility responses rise.

Assessment

This is a real trade-off, not a free gain. The exchequer and perceived tax fairness benefit, while asset owners and some entrepreneurs bear most costs. Overall output depends on behaviour, capacity and pass-through.

Confidence: Medium-low. Higher on the policy target and fiscal channel; lower on behaviour, pass-through and economy-wide effects.

Main risks

  • Behavioural response: Avoidance, timing and relocation can reduce receipts.
  • Incidence uncertainty: Legal taxpayers may shift costs to workers, consumers or investors.
  • Investment risk: Higher taxes can reduce investment where returns are mobile.

Safeguards

  • Use HMRC microsimulation before legislating.
  • Close avoidance routes before rate rises.
  • Review receipts and investment annually.

Academic evidence

Mirrlees and review team, Institute for Fiscal Studies, 2011

Tax by Design

Efficient tax systems should avoid narrow bases and poorly targeted reliefs that distort decisions.

Useful benchmark for judging tax-base changes and exemptions.

Tax by Design (2011)

UK government evidence

Sources

Other Liberal Democrats policies

PolicyLens estimates are illustrative and should not be treated as official costings.