For a UK sole trader, Claude Pro and ChatGPT Plus subscriptions are allowable expenses under HMRC's wholly-and-exclusively test (BIM37007) only when paid from the business account and used for trade purposes; the business-tier seats (Claude Team £24/user/month, ChatGPT Business $25/user/month) are cleaner deductibles above £50k turnover because the personal-use exposure is structurally lower and the audit trail is built for the trade. Reverse-charge VAT applies on Anthropic invoices (US entity) and OpenAI invoices (Ireland entity invoicing most UK customers) under VAT Notice 741A place-of-supply rules; Microsoft Copilot UK plans invoice via Microsoft UK Ltd with VAT on the invoice. The MTD-ITSA regime that landed 6 Apr 2026 (mandatory at £50k combined trading + property income, dropping to £30k in Apr 2027 and £20k in Apr 2028) requires every AI-vendor invoice to be captured in HMRC-recognised software at the point it lands; FreeAgent is the practitioner default for UK sole traders under £200k turnover (Open Banking feed, receipt capture included, reliable AI-vendor categorisation), Xero scales better as headcount appears, QuickBooks works but its UK MTD-ITSA module is the youngest of the three. The practical trigger to switch from consumer-tier (Pro / Plus) to business-tier (Team / Business) is VAT registration: the £4-7/month/seat uplift is below the noise floor; the wholly-and-exclusively defence, the admin console, and the audit trail justify the move.

Operators register, UK regional anchor — first UK-specific piece in the register (existing 44 OPS posts are NL/DE-heavy with zero UK coverage). Cadence 21 days through the rest of 2026 because MTD-ITSA secondary guidance is still landing and because OpenAI and Anthropic have each changed UK billing-entity arrangements once during the post-Brexit transition; cadence moves to 45 days from 1 Jan 2027. Anchor sources cited inline in the article: HMRC BIM37007 (wholly-and-exclusively test) and BIM37600 (dual-purpose apportionment), HMRC VAT Notice 741A (place of supply of services), the gov.uk MTD for Income Tax collection page, the gov.uk MTD-ITSA recognised-software list, OpenAI pricing page (chatgpt/pricing), Anthropic legal terms (claude.com/legal — for billing entity confirmation). Trigger conditions to revisit before next cadence: (a) HMRC publishes specific AI-tool guidance under BIM37007 or BIM37600 — would either tighten the apportionment standard or loosen the business-tier recommendation; (b) OpenAI or Anthropic changes UK invoicing entity (each has done this once already during the post-Brexit transition); (c) MTD-ITSA threshold timeline shifts — the Apr 2026 / Apr 2027 / Apr 2028 ladder has been delayed three times historically and a fourth delay would push the urgency on accounting-software selection out, though the FreeAgent-for-sole-traders-under-£200k recommendation is independent of the deadline; (d) a major UK accounting-software vendor releases AI-vendor-specific auto-categorisation that materially changes the FreeAgent / Xero / QuickBooks comparison; (e) HMRC opens a section 9A enquiry track that targets AI-subscription expense entries — would tighten the categorisation guidance materially. Sister claims: OPS-031 (AI bookkeeping NL — Moneybird/e-Boekhouden parallel), OPS-055 (AI bookkeeping DE — DATEV/sevDesk/Lexware parallel), OPS-039 (AI invoicing VAT compliance — the inverse flow for sole traders selling AI-augmented services). The £50k MTD-ITSA threshold confirmed against HMRC guidance landing 6 Apr 2026; if the timeline shifts in a future Finance Bill the threshold figure in this claim updates, but the wholly-and-exclusively reasoning and the business-tier-seat recommendation are independent of MTD-ITSA timing.