It is 10pm. A client has just forwarded an SA370 penalty notice from HMRC. Late filing penalty: £1,200 plus daily £10 charges that started running three months ago. Reply deadline: 30 days from notice date. You have 11 other active HMRC notices for other clients and a CT600 due on Friday. The formal response letter — citing the reasonable excuse provisions under TMA 1970 s118, HMRC's Employment and Self-Assessment Penalty guidance, and requesting penalty suspension — will take you four to six hours to draft from scratch.
HMRCGuard AI processes the same notice in 60 seconds. Not a template — a full formal CA response letter that extracts the UTR, taxpayer name, reference number, tax year, response deadline, and amount at issue. Then Groq Llama-3.1-70b generates a letter in standard HMRC correspondence format with the correct legislation citations, appropriate formal register, and an ICAEW signature block placeholder.
What HMRC notice types does it handle?
HMRCGuard AI handles the most common HMRC notices issued to individuals and companies:
SA326 — Surcharge on unpaid Income Tax (5% of unpaid tax after 30 days and 6 months) SA370 — Fixed penalty for late Self Assessment filing (£100 automatic, £10/day after 3 months) SA372 — Penalty for failure to notify chargeability to Income Tax CT620 — Notice of enquiry into a Company Tax Return under CTA 2009 VAT654 — VAT assessment under VATA 1994 s73 for under-declared or over-claimed VAT CC/FS1 — HMRC compliance check opening letter (30-day response window) CC/FS7 — HMRC notice of criminal investigation under PACE 1984 COP8 — Code of Practice 8 for suspected serious non-deliberate non-compliance COP9 — Code of Practice 9 for suspected fraud (the most serious HMRC notice)
Upload a PDF or scanned document — the AI extracts all structured fields and identifies the specific notice type.
The AI extraction and letter generation pipeline
Step 1 — Field extraction: The AI reads the notice and extracts UTR (10-digit Unique Taxpayer Reference), VRN (VAT Registration Number if applicable), HMRC reference number, notice date, response deadline, amount at issue in pence (stored as integers to avoid floating-point errors, displayed as GBP), tax type (Income Tax / Corporation Tax / VAT / PAYE / NIC / CGT), tax year (e.g. 2023–24), and the specific issues HMRC has raised.
Step 2 — Letter generation: The AI writes a formal response letter in standard UK correspondence format. It opens with the taxpayer's details block (name, address placeholder, UTR/VRN, date), states the formal subject line ('Re: Response to SA370 dated [date] — Ref: [reference]'), acknowledges receipt, responds to each HMRC issue with appropriate UK legislation cited, and where applicable requests reasonable excuse consideration or penalty suspension under Finance Act 2007 Schedule 24.
Step 3 — CA briefing: A separate CA briefing note summarises what HMRC wants, what documents to gather from the client, the penalty exposure if the deadline is missed, a strategic recommendation, the typical response window for this notice type, and the relevant legislation references (TCGA 1992, ITA 2007, CTA 2010, VATA 1994, FA sections).
COP9 notices: what AI can and cannot do
COP9 is the most serious HMRC notice — it indicates HMRC suspects serious tax fraud and gives the taxpayer the opportunity to make a full disclosure via the Contractual Disclosure Facility (CDF) before HMRC launches a criminal investigation.
HMRCGuard AI flags COP9 notices prominently with a red alert and explicitly warns that a specialist tax barrister or CIOT-qualified Chartered Tax Adviser must be engaged before any response is drafted. The AI does not generate a COP9 response letter — this is intentional. COP9 requires strategic decisions about whether to accept CDF or contest, and those decisions have criminal law consequences. The AI's role here is to help the CA identify the notice immediately, understand its seriousness, and escalate correctly — not to automate a response that could harm the client.
CC/FS7 (criminal investigation under PACE 1984) is handled the same way: red alert, no auto-draft, explicit escalation guidance.
What the CA still does
The AI letter is a starting point for CA review, not a filing-ready document. The CA checks extracted fields against HMRC correspondence and client records, adds case-specific facts (the actual reason for late filing, supporting evidence references, client circumstances), reviews all legislation citations for accuracy, and signs the letter on firm headed notepaper before sending by Royal Mail Recorded Delivery.
The time saving is in eliminating blank-page time and boilerplate drafting. The CA's judgment goes into the case-specific content — not into remembering whether the TMA 1970 s118 reasonable excuse provision applies to this penalty type or what the standard HMRC correspondence structure should look like.
Real time and cost savings for a UK CA practice
A CA practice handling 20 HMRC notices per month, at 5 hours average drafting time per notice: 100 hours/month on notice response drafting. At a charge-out rate of £150/hour, that is £15,000 of chargeable time spent on mechanical drafting per month.
HMRCGuard AI is available on the Pro plan at £10/month. The ROI in the first month is approximately 1,500×.
More practically: a COP9 notice or CC/FS1 that arrives on a Thursday afternoon no longer means a weekend drafting session. The AI produces the first draft in 60 seconds. The CA reviews it in 30 minutes. The client has a response by Friday morning.
Getting started
HMRCGuard AI is available to UK CA firms on OpsOracle AI Pro at £10/month. Upload a PDF of the HMRC notice, review the extracted fields, and a formal response letter is ready for CA review in under 90 seconds. The dashboard tracks all active notices with urgency classification — overdue, critical (≤14 days), warning, and normal — so every notice with a live deadline is visible across the practice.