Primary Legislation
Acts of Parliament and Finance Acts forming the legal foundation of UK tax law.
Authority level: Highest
Used for: Core legal rules, rates, definitions, reliefs
Sources you can trustGAIN Tax is designed to support tax professionals using primary and secondary legislation, supported by HMRC materials, with a transparent source hierarchy.
Core sourcesActs of Parliament and Finance Acts forming the legal foundation of UK tax law.
Authority level: Highest
Used for: Core legal rules, rates, definitions, reliefs
Statutory Instruments providing detailed rules and practical application.
Authority level: High
Used for: Regulations, commencement rules, detailed provisions
Manuals and guidance supporting interpretation and real-world application.
Authority level: Supporting
Used for: Practical interpretation, examples, administrative guidance
Source hierarchy sectionPrimary legislation
The strongest authority. Used first where available.
Secondary legislation
Used for detailed rules and statutory implementation.
HMRC guidance and manuals
Used to support interpretation and practical application.
Legislation always takes precedence over guidance.
Important
Where legislation and guidance differ, GAIN Tax treats legislation as the higher authority.
How GAIN Tax worksGAIN Tax follows a structured process to connect user questions with relevant tax materials.
The system identifies the relevant tax area, date context, and likely legal provisions.
GAIN Tax searches applicable legislation, statutory instruments, and HMRC materials.
Retrieved materials are assessed for authority, timing, context, and fit to the question.
The answer is drafted with structured reasoning and traceable citations.
Updates & coverageUpdated as new laws and amendments are published.
Monitored and refreshed regularly.
Ongoing enhancements to retrieval, accuracy, and citation quality.
Versioning & effective datesWork with the right law — at the right time.
Query:"What is the BADR rate?"
Result:Uses the current legal position.
Query:"What was the BADR rate on 1 June 2025?"
Result:Uses the law in force on that date.
UK regional coverageGAIN Tax is designed to apply the relevant framework where tax rules differ across UK jurisdictions.
Detects when rules differ by jurisdiction
Applies the relevant legislation and guidance
Aligns outputs with the appropriate regional framework
Best use casesGAIN Tax is most effective when used as a research and drafting assistant for professional tax work.
Identify relevant legislation and HMRC materials faster.
Move through complex tax provisions with clearer direction.
Prepare memorandums, formal letters, and structured explanations.
Analyse facts and identify potential tax issues.
Review documents for possible tax considerations.
LimitationsGAIN Tax is a research and drafting assistant. It supports professional review, but users remain responsible for applying judgement to specific facts and client circumstances.
Transparency sectionGAIN Tax continues to improve source coverage, update processes, retrieval accuracy, and citation quality.
Source coverage
Update processes
Retrieval accuracy
Citation quality
Feedback from tax professionals is an important part of this process.
