Primary sources · 158 pages

Sources we use

Every guide is written from primary sources: GOV.UK guidance, HMRC’s internal manuals and helpsheets, and the legislation itself. Here they all are, with the pages that rely on each one.

gov.uk

• GOV.UK: Appoint someone to deal with HMRC on your behalf Used in: When to get professional help
• GOV.UK: Business Asset Disposal Relief — eligibility Used in: Key figures
• GOV.UK: Business records if you’re self-employed — How long to keep your records Used in: Records and evidence HMRC may ask for
• GOV.UK: Capital Gains Tax rates Used in: Key figures
• GOV.UK: Capital Gains Tax rates and allowances Used in: How capital losses are set against gains — and the annual exempt amount · Key figures
• GOV.UK: Capital Gains Tax — enquiries Used in: When to get professional help
• GOV.UK: Capital Gains Tax — If you make a loss Used in: Capital losses: what counts as an allowable loss · Deadlines for loss claims · How to claim a capital loss — and the 4-year time limit · How capital losses are set against gains — and the annual exempt amount · Losses on disposals to family and connected people · Losses when you sell property — and the 60-day UK property return
• GOV.UK: Capital Gains Tax — Record keeping Used in: Capital losses: what counts as an allowable loss · Records and evidence HMRC may ask for
• GOV.UK: Capital Gains Tax — What you pay it on Used in: Capital losses: what counts as an allowable loss
• GOV.UK: Capital Gains Tax — work out if you need to pay Used in: Key figures
• GOV.UK: Carry forward Corporation Tax losses Used in: Company trading losses: an overview
• GOV.UK: Cash basis Used in: Losses under the cash basis
• GOV.UK: Check how to register for Self Assessment Used in: Deadlines for loss claims
• GOV.UK: Check if you need to pay tax when you sell cryptoassets Used in: Records and evidence HMRC may ask for · Cryptoasset losses
• GOV.UK: Corporation Tax rates and allowances Used in: Company trading losses: an overview · Key figures
• GOV.UK: Corporation Tax — terminal, capital and property income losses Used in: Company trading losses: an overview
• GOV.UK: Find out if and when you need to use Making Tax Digital for Income Tax Used in: Making Tax Digital for Income Tax from April 2026 · Key figures
• GOV.UK: Find out if you can get an exemption from Making Tax Digital for Income Tax Used in: Making Tax Digital for Income Tax from April 2026
• GOV.UK: HMRC compliance checks — help and support Used in: When to get professional help
• GOV.UK: How to choose a tax agent Used in: When to get professional help
• GOV.UK: Income Tax rates and allowances for current and previous tax years Used in: Key figures
• GOV.UK: Income Tax rates and Personal Allowances Used in: Key figures
• GOV.UK: Keeping your pay and tax records — How long to keep your records Used in: Records and evidence HMRC may ask for
• GOV.UK: Making Tax Digital for Income Tax for sole traders and landlords — step by step Used in: Making Tax Digital for Income Tax from April 2026
• GOV.UK: Negligible value claims and agreements Used in: Shares that have become worthless: negligible value claims
• GOV.UK: Penalties for Making Tax Digital for Income Tax Used in: Making Tax Digital for Income Tax from April 2026
• GOV.UK: Report and pay Capital Gains Tax — if you sold a property in the UK Used in: Losses when you sell property — and the 60-day UK property return
• GOV.UK: Report and pay your Capital Gains Tax Used in: Deadlines for loss claims
• GOV.UK: Report your Capital Gains Tax on UK property by post Used in: Losses when you sell property — and the 60-day UK property return
• GOV.UK: Self Assessment tax returns — Deadlines Used in: Deadlines for loss claims
• GOV.UK: Self Assessment tax returns — If you need to change your return Used in: Amending a return or claiming later
• GOV.UK: Self Assessment tax returns — Penalties Used in: Deadlines for loss claims
• GOV.UK: Self Assessment — general enquiries Used in: When to get professional help
• GOV.UK: Stop being self-employed Used in: Terminal loss relief when a business stops
• GOV.UK: Tell HMRC about Capital Gains Tax on UK property or land if you’re not a UK resident Used in: Losses when you sell property — and the 60-day UK property return
• GOV.UK: Use Making Tax Digital for Income Tax — Adjust your self-employment and property income Used in: Making Tax Digital for Income Tax from April 2026
• GOV.UK: Use Making Tax Digital for Income Tax — Send quarterly updates Used in: Making Tax Digital for Income Tax from April 2026
• GOV.UK: Use Making Tax Digital for Income Tax — Submit your tax return Used in: Amending a return or claiming later · Making Tax Digital for Income Tax from April 2026
• GOV.UK: Work out and claim relief from Corporation Tax trading losses Used in: Company trading losses: an overview
• GOV.UK: Work out your qualifying income for Making Tax Digital for Income Tax Used in: Making Tax Digital for Income Tax from April 2026
• GOV.UK: Work out your rental income when you let property Used in: Rental (UK property business) losses
• GOV.UK: Work out your tax if you’re a non-resident selling UK property or land Used in: Losses when you sell property — and the 60-day UK property return
• HMRC: Additional information SA101 and notes Used in: Where losses go on your Self Assessment return
• HMRC: Partnership (full) SA104F and notes Used in: Where losses go on your Self Assessment return · Partnership losses
• HMRC: SA104S Partnership (short) notes 2026 Used in: Setting a trading loss against other income (sideways relief) · Where losses go on your Self Assessment return · Partnership losses
• HMRC: SA105 UK property pages and notes (2025–26) Used in: Rental (UK property business) losses · Where losses go on your Self Assessment return
• HMRC: SA108 Capital Gains Tax summary notes (2025–26 edition) Used in: Capital losses: what counts as an allowable loss · How to claim a capital loss — and the 4-year time limit · Where losses go on your Self Assessment return · Losses on disposals to family and connected people · Shares that have become worthless: negligible value claims · Share loss relief: setting a loss on shares against income · Cryptoasset losses
• HMRC: Self-employment (full) SA103F and notes Used in: Where losses go on your Self Assessment return · Carrying a trading loss forward
• HMRC: Self-employment (short) SA103S and notes Used in: Where losses go on your Self Assessment return · Early years loss relief: losses in the first four years
• HMRC Business Income Manual BIM70000: Cash basis Used in: Losses under the cash basis
• HMRC Business Income Manual BIM72010: Cash basis eligibility Used in: Losses under the cash basis
• HMRC Business Income Manual BIM81201: Tax year basis from 2024-25 Used in: Self-employed losses: your options at a glance
• HMRC Business Income Manual BIM85000: Trade losses Used in: Losses under the cash basis
• HMRC Business Income Manual BIM85010: Trade losses — types of relief Used in: Self-employed losses: your options at a glance
• HMRC Business Income Manual BIM85015: Relief against general income Used in: Setting a trading loss against other income (sideways relief)
• HMRC Business Income Manual BIM85030: Relief against chargeable gains Used in: Setting a trading loss against other income (sideways relief)
• HMRC Business Income Manual BIM85045: Relief for losses in early years Used in: Early years loss relief: losses in the first four years
• HMRC Business Income Manual BIM85050: Early years — when a trade is first carried on Used in: Early years loss relief: losses in the first four years
• HMRC Business Income Manual BIM85055: Terminal loss relief Used in: Terminal loss relief when a business stops
• HMRC Business Income Manual BIM85060: Carry forward of losses Used in: Carrying a trading loss forward
• HMRC Business Income Manual BIM85065: Trade losses — claims to relief Used in: Self-employed losses: your options at a glance
• HMRC Business Income Manual BIM85070: Claims involving more than one year Used in: Setting a trading loss against other income (sideways relief) · Amending a return or claiming later · Carrying a trading loss forward
• HMRC Business Income Manual BIM85075: Time limits for trade loss claims Used in: Deadlines for loss claims · Setting a trading loss against other income (sideways relief) · Carrying a trading loss forward · Terminal loss relief when a business stops
• HMRC Business Income Manual BIM85080: Part claims and priority of claims Used in: Self-employed losses: your options at a glance
• HMRC Business Income Manual BIM85703: The cap on reliefs Used in: The cap on loss relief and other restrictions
• HMRC Business Income Manual BIM85705: Commercial basis Used in: The cap on loss relief and other restrictions
• HMRC Business Income Manual BIM85735: Uncommercial losses in early years Used in: Early years loss relief: losses in the first four years
• HMRC Business Income Manual BIM85765: Non-active traders Used in: The cap on loss relief and other restrictions
• HMRC Capital Gains Manual CG-APP18-250: CGT on UK property account — losses and exemptions Used in: Losses when you sell property — and the 60-day UK property return
• HMRC Capital Gains Manual CG-APP18-260: Filing where there is no liability Used in: Losses when you sell property — and the 60-day UK property return
• HMRC Capital Gains Manual CG-APP18-320: Self Assessment and the property account Used in: Losses when you sell property — and the 60-day UK property return
• HMRC Capital Gains Manual CG13125: Negligible value claims Used in: Shares that have become worthless: negligible value claims
• HMRC Capital Gains Manual CG13130: Negligible value — date of claim Used in: Shares that have become worthless: negligible value claims
• HMRC Capital Gains Manual CG14561: Connected persons — losses Used in: Losses on disposals to family and connected people
• HMRC Capital Gains Manual CG15800: Losses — allowable losses Used in: Capital losses: what counts as an allowable loss · How to claim a capital loss — and the 4-year time limit
• HMRC Capital Gains Manual CG15831: Losses set against income Used in: Share loss relief: setting a loss on shares against income
• HMRC Capital Gains Manual CG18000: Annual exempt amount Used in: How capital losses are set against gains — and the annual exempt amount
• HMRC Capital Gains Manual CG21500: Individuals — losses Used in: How to claim a capital loss — and the 4-year time limit · How capital losses are set against gains — and the annual exempt amount
• HMRC Capital Gains Manual CG21520: Losses — examples 1 to 5 Used in: How capital losses are set against gains — and the annual exempt amount
• HMRC Company Taxation Manual CTM04100: Losses carried forward Used in: Company trading losses: an overview
• HMRC Company Taxation Manual CTM04135: Carry-forward claims Used in: Company trading losses: an overview
• HMRC Company Taxation Manual CTM04505: Relief against total profits Used in: Company trading losses: an overview
• HMRC Company Taxation Manual CTM04830: Loss restriction Used in: Company trading losses: an overview · Key figures
• HMRC Company Taxation Manual CTM80105: Group relief outline Used in: Company trading losses: an overview
• HMRC Company Taxation Manual CTM80151: The group relationship Used in: Company trading losses: an overview
• HMRC Company Taxation Manual CTM97045: Group relief time limit Used in: Company trading losses: an overview
• HMRC Cryptoassets Manual CRYPTO22100: What is a disposal Used in: Cryptoasset losses
• HMRC Cryptoassets Manual CRYPTO22400: Loss or theft of private keys Used in: Cryptoasset losses
• HMRC Cryptoassets Manual CRYPTO22450: Theft, hacks and fraud Used in: Cryptoasset losses
• HMRC Cryptoassets Manual CRYPTO22500: Negligible value claims Used in: Cryptoasset losses
• HMRC factsheet CC/FS1a: About compliance checks Used in: Records and evidence HMRC may ask for
• HMRC helpsheet HS204: Limit on Income Tax reliefs (2026) Used in: Where losses go on your Self Assessment return · The cap on loss relief and other restrictions · Key figures
• HMRC helpsheet HS223: Rent a Room Scheme (2026) Used in: Rental (UK property business) losses
• HMRC helpsheet HS227: Relief for trading losses (2026) Used in: Self-employed losses: your options at a glance · Setting a trading loss against other income (sideways relief) · Where losses go on your Self Assessment return · Amending a return or claiming later · Carrying a trading loss forward · Early years loss relief: losses in the first four years · Making Tax Digital for Income Tax from April 2026 · Terminal loss relief when a business stops · The cap on loss relief and other restrictions · Partnership losses
• HMRC helpsheet HS281: Capital Gains Tax — civil partners and spouses Used in: Losses on disposals to family and connected people
• HMRC helpsheet HS282: Death, personal representatives and legatees Used in: How capital losses are set against gains — and the annual exempt amount
• HMRC helpsheet HS286: Negligible value claims and Income Tax losses for shares (2026) Used in: Shares that have become worthless: negligible value claims · Share loss relief: setting a loss on shares against income
• HMRC Partnership Manual PM163080: Partner’s notional trade Used in: Partnership losses
• HMRC Partnership Manual PM191000: Loss claims and restrictions Used in: Partnership losses
• HMRC Partnership Manual PM191300: Claims that affect a partner’s tax Used in: Partnership losses
• HMRC Partnership Manual PM193000: The £25,000 annual limit Used in: Partnership losses
• HMRC Property Income Manual PIM1092: Cash basis for landlords Used in: Losses under the cash basis
• HMRC Property Income Manual PIM2058: Finance cost restriction Used in: Rental (UK property business) losses
• HMRC Property Income Manual PIM4205: Losses — overview Used in: Rental (UK property business) losses
• HMRC Property Income Manual PIM4210: Setting losses against future profits Used in: Rental (UK property business) losses
• HMRC Property Income Manual PIM4220: Setting losses against general income Used in: Rental (UK property business) losses
• HMRC Property Income Manual PIM4228: Restriction on sideways relief Used in: Rental (UK property business) losses
• HMRC Self Assessment Claims Manual SACM3030: Claims outside a return Used in: Amending a return or claiming later
• HMRC Self Assessment Claims Manual SACM3035: Time limits Used in: Deadlines for loss claims
• HMRC Self Assessment Claims Manual SACM4015: Records for claims outside a return Used in: Records and evidence HMRC may ask for
• HMRC Self Assessment Claims Manual SACM12155: Overpayment relief time limits Used in: Amending a return or claiming later
• HM Treasury / HMRC policy paper: Expanding the cash basis Used in: Losses under the cash basis

legislation.gov.uk

• Corporation Tax Act 2010 section 269ZR Used in: Key figures
• Corporation Tax Act 2010, section 37 Used in: Company trading losses: an overview · Deadlines for loss claims
• Corporation Tax Act 2010, section 39 Used in: Company trading losses: an overview
• Corporation Tax Act 2010, section 45A Used in: Company trading losses: an overview
• Finance Act 2019, Schedule 2 (returns for disposals of UK land) Used in: Losses when you sell property — and the 60-day UK property return
• Finance Act 2025, Schedule 5 (furnished holiday lettings abolition) Used in: Rental (UK property business) losses
• Income Tax Act 2007, section 24A (limit on certain reliefs) Used in: Share loss relief: setting a loss on shares against income · The cap on loss relief and other restrictions · Key figures
• Income Tax Act 2007, section 60 Used in: Self-employed losses: your options at a glance
• Income Tax Act 2007, section 64 Used in: Deadlines for loss claims · Setting a trading loss against other income (sideways relief)
• Income Tax Act 2007, section 66 (commercial basis) Used in: Setting a trading loss against other income (sideways relief) · The cap on loss relief and other restrictions
• Income Tax Act 2007, section 67 (farming) Used in: The cap on loss relief and other restrictions
• Income Tax Act 2007, section 72 Used in: Early years loss relief: losses in the first four years
• Income Tax Act 2007, section 73 Used in: Early years loss relief: losses in the first four years
• Income Tax Act 2007, section 74 Used in: Early years loss relief: losses in the first four years
• Income Tax Act 2007, section 74A (non-active traders) Used in: The cap on loss relief and other restrictions · Key figures
• Income Tax Act 2007, section 74C (10-hour test) Used in: The cap on loss relief and other restrictions
• Income Tax Act 2007, section 74E (omitted from 2024-25) Used in: Losses under the cash basis
• Income Tax Act 2007, section 83 Used in: Carrying a trading loss forward
• Income Tax Act 2007, section 84 Used in: Carrying a trading loss forward
• Income Tax Act 2007, section 89 Used in: Terminal loss relief when a business stops
• Income Tax Act 2007, section 90 Used in: Terminal loss relief when a business stops
• Income Tax Act 2007, section 91 Used in: Terminal loss relief when a business stops
• Income Tax Act 2007, section 103C (limited and non-active partners) Used in: The cap on loss relief and other restrictions · Partnership losses · Key figures
• Income Tax Act 2007, section 104 (limited partners) Used in: Partnership losses
• Income Tax Act 2007, section 110 (non-active partners in early years) Used in: Partnership losses
• Income Tax Act 2007, section 118 Used in: Rental (UK property business) losses
• Income Tax Act 2007, section 120 Used in: Rental (UK property business) losses
• Income Tax Act 2007, section 123 Used in: Rental (UK property business) losses
• Income Tax Act 2007, section 124 Used in: Deadlines for loss claims · Rental (UK property business) losses
• Income Tax Act 2007, section 127BA Used in: Rental (UK property business) losses · Losses under the cash basis
• Income Tax Act 2007, section 131 (share loss relief) Used in: Share loss relief: setting a loss on shares against income
• Income Tax Act 2007, section 132 Used in: Deadlines for loss claims · Share loss relief: setting a loss on shares against income
• Income Tax Act 2007, section 989 (normal filing date) Used in: Setting a trading loss against other income (sideways relief)
• Taxation of Chargeable Gains Act 1992, section 1 Used in: How capital losses are set against gains — and the annual exempt amount
• Taxation of Chargeable Gains Act 1992, section 1F (deduction of losses) Used in: How capital losses are set against gains — and the annual exempt amount
• Taxation of Chargeable Gains Act 1992, section 1K (annual exempt amount) Used in: How capital losses are set against gains — and the annual exempt amount · Key figures
• Taxation of Chargeable Gains Act 1992, section 16 Used in: Capital losses: what counts as an allowable loss · How to claim a capital loss — and the 4-year time limit
• Taxation of Chargeable Gains Act 1992, section 18 Used in: Losses on disposals to family and connected people
• Taxation of Chargeable Gains Act 1992, section 24 Used in: Deadlines for loss claims · Shares that have become worthless: negligible value claims
• Taxation of Chargeable Gains Act 1992, section 58 (spouses and civil partners) Used in: Losses on disposals to family and connected people
• Taxation of Chargeable Gains Act 1992, section 62 (death) Used in: How capital losses are set against gains — and the annual exempt amount
• Taxation of Chargeable Gains Act 1992, section 261B Used in: Setting a trading loss against other income (sideways relief)
• Taxes Management Act 1970, Schedule 1A (claims outside a return) Used in: Amending a return or claiming later · Records and evidence HMRC may ask for
• Taxes Management Act 1970, section 9ZA Used in: Amending a return or claiming later
• Taxes Management Act 1970, section 12B Used in: Records and evidence HMRC may ask for
• Taxes Management Act 1970, section 43 Used in: Deadlines for loss claims · How to claim a capital loss — and the 4-year time limit · Carrying a trading loss forward

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