U
- UCITS – see Undertakings for collective investment in transferable securities (UCITS)
- UK company
- UK connection condition
- UK establishment – see Business establishment
- UK funds
- UK law
- UK lessor leasing to non-resident lessee
- UK permanent establishment
- UK permanent establishment of non-UK resident company to UK resident company, transfer of
- UK property losses
- UK real estate investment trusts – see Real estate investment trusts (REITs)
- UK representatives
- UK resident
- UK residents doing business outside UK
- UK-Swiss confederation taxation cooperation agreement
- UK-US FATCA agreement
- UK/Swiss confederation
- Ulster Museum
- Ulster savings certificates
- Ultra vires payments
- Umbrella businesses
- Umbrella companies
- Umbrella contracts of service
- Umbrella funds
- Umbrella schemes
- Unadministered estate
- Unallocated commodities – see Commodities
- Unallowable purpose
- Unapproved retirement benefit schemes – see Retirement benefit schemes, Non-approved pension schemes
- Unapproved share schemes
- Unascertainable consideration
- Unauthorised issue of invoices – see Invoices
- Unauthorised payments
- Unauthorised unit trust schemes
- Unauthorised unit trusts – see Unit trusts
- Unauthorised work
- Unbinding
- Uncertain consideration
- Uncertainty
- Unclaimed money
- Unclaimed monies
- Uncommercial rents
- Uncommercial trades
- Under-declared levy
- Underassessment of tax
- Underdeclarations
- Underleases – see Leases and leasing
- Underlying tax – see Double taxation relief
- Underpaid National Insurance contributions – see National Insurance contributions (NICs)
- Underpaid tax – see Unpaid tax
- Underpayment of tax – see Unpaid tax
- Underpayments
- Understatements
- Undertakers – see Burial and cremation
- Undertakings – see Transfers of undertakings, Undertakings given to HM Revenue and Customs
- Undertakings for collective investment in transferable securities (UCITS)
- Undertakings given to HM Revenue and Customs
- Undervalue
- Underwater options
- Underwriters – see Lloyd's underwriters (corporate members), Lloyd's underwriters (individuals), Lloyd's underwriters
- Underwriting
- Underwriting commissions
- Undisclosed agents
- Undistributed income
- Unemployability supplement
- Unemployment benefit
- Unemployment benefits
- Unfair dismissal of employees
- Unfinished houses
- Unfunded schemes
- Unified Budget – see Budget (The)
- Uniform allowances – see Armed forces, Clothing
- Uniforms
- Unilateral relief
- Unilateral relief arrangements
- Unincorporated associations
- Unincorporated bodies
- Unincorporated businesses
- Unions – see Trade unions
- Unique taxpayer reference
- Unique Taxpayer Reference (UTR)
- Unit trust scheme relief
- Unit trust schemes
- Unit trusts
- Unit-trust schemes
- Unit-trust units
- Unitary taxation
- United Kingdom
- United Kingdom Atomic Energy Authority
- United Kingdom Warning and Monitoring Organisation
- United Nations
- United Nations Educational, Scientific and Cultural Organisation
- United Nations Industrial Development Organisation
- United Nations Model Convention
- United States
- United States Air Force – see Visiting forces
- United States forces
- United States Government
- United States taxpayers
- Universal credit
- Universal Postal Union
- Universities
- University costs
- Unjust enrichment
- Unlawful conduct
- Unlawful killing – see Forfeiture rule
- Unlawful trading
- Unless orders
- Unlisted securities – see Unquoted/unlisted shares and securities
- Unlisted Securities Market
- Unmarried couples
- Unmarried couples living together
- Unmarried mother
- Unmarried persons – see Married couples and civil partners
- Unpaid contributions
- Unpaid duty
- Unpaid levy
- Unpaid remuneration
- Unpaid tax
- Unpaid VAT
- Unquoted companies
- Unquoted company
- Unquoted or unlisted shares and securities
- Unquoted/unlisted shares and securities
- Unreasonable conduct
- Unregistered friendly societies – see Friendly societies
- Unregistered persons
- Unregistered traders
- Unregulated gas and electricity suppliers and utilities
- Unrelieved double tax
- Unrelieved qualifying expenditure
- Unremittable foreign income
- Unremittable income
- Unremittable trade debts
- Unstamped documents
- Unused parts of a dwelling-house
- Unwinding schemes
- Up-front childcare fund
- Up-front childcare fund payments
- Uplift – see Petroleum revenue tax
- Upper earnings limit
- Upper Tax Tribunal
- Upper Tribunal
- Urban regeneration companies
- Urns – see Burial and cremation
- US pensions
- USA's Foreign Account Tax Compliance Act
- Used cars – see Motor vehicles, Second-hand goods scheme
- USSR
- USSR treaty
- US–UK Agreement
- Utility costs