HMRC published Guidelines for Compliance GfC19 on 13 August 2026: Help with short-term business visitors. ICAEW flagged it in its 19 August tax news brief. It is not a law change. It is HMRC’s plain map of a control failure that still burns groups with international travel, secondments and multi-state commuters.
The misconception is simple: “they’re only here a few days, so there’s no UK PAYE and no NIC.” Wrong. One UK workday can create a UK Income Tax charge. Treaty relief does not switch PAYE off automatically. National Insurance sits on a completely separate track from double tax treaties. If mobility, payroll and tax still treat STBVs as a side issue, this is what HMRC will wave in the next employer compliance check.
Primary sources: the GfC19 hub, Part 1, Part 2 (Income Tax / EP App 4 & 8), Part 3 (NIC), Part 4 (errors & checks), the Guidelines for Compliance collection, PAYE82000, PAYE81950, PAYE81500, DT1920, EIM40000, NIM33550 and ICAEW’s brief.
What GfC19 covers
Guidelines for Compliance set out HMRC’s view on complex, widely misunderstood risks. GfC19 sits under employer duties and covers PAYE, Income Tax and NIC for people who normally work outside the UK but perform duties here temporarily.
HMRC’s definition is wider than many travel policies admit:
- Short-term assignees — formal assignments up to six months
- Business travellers — regular trips or one-off meetings
- Project workers — variable-length deployments
- Multi-state commuters — living in one country, working regularly in another
If you only track formal assignees, you are already under-scoped.
The Income Tax and PAYE core
Employment income relating to duties physically performed in the UK is ordinarily within the UK charge. Residence is tested under the Statutory Residence Test. For a non-UK resident year, only UK-duties earnings are in charge (see also EIM40203 on incidental duties).
Where a double tax treaty applies, the UK often gives up taxing rights if classic employment-article tests are met — typically under 183 days, not paid by or on behalf of a UK employer, and cost not ultimately borne by a UK PE. Check the specific treaty. GfC19 is blunt: treaty relief is claimed, not assumed. Even where no UK Income Tax remains after the claim, earnings can still be PAYE income. Without a special arrangement, a UK-present employer — or the UK host — may still need PAYE from day one, with reclaim via Self Assessment.
For treaty 183-day tests, a “day” is physical presence at any time that day — arrival and departure included, weekends and leave included. That is not the SRT definition. GfC19’s example: arrive Sunday 20 April, work Mon–Fri, stay the weekend, fly Monday 28 April morning = nine treaty days. Transit between two non-UK locations does not count. If your tracker only logs office days, your headroom is fiction.
EP Appendix 4
EP Appendix 4 lets HMRC agree the UK employer need not operate PAYE on qualifying STBVs. Headline conditions: treaty-country residence with a usable employment article; coming to work for a UK company/branch (or legally UK-employed but economically employed offshore); earnings not ultimately borne by a UK employer (subject to the 60-day rule); expected stay ≤ 183 days in the treaty period.
Overseas branches of a UK company are not separate entities. Branch staff cannot sit in Appendix 4. That still catches groups that “park” people on branch payrolls.
60-day rule. Presence under 60 days that is not part of a more substantial UK period may still allow Appendix 4 even where a UK PE bears cost — HMRC may not treat the UK as economic employer. Misapplying this is on HMRC’s error list. Read the Tax Bulletin 68 examples before you lean on it.
Economic employer. Who gets the benefit of the work? Who bears the risk? Who directs and supervises? Recharges matter, but so do reporting lines. GfC19 walks OECD Article 15 commentary examples — genuine outbound service contracts versus body-shopping under UK supervision. If your UK opco runs the visitor’s day job and pays a fully loaded recharge, do not be surprised if treaty/Appendix 4 conditions fail.
Reporting. Apply via Shared Workspace or in writing to Charities, Savings & International 3, HMRC, BX9 1AJ. Annual reports are due by 31 May, banded by UK days (1–60 / 61–90 / 91–150 / 151–183). HMRC expects movement tracking and central reporting once intermittent UK days exceed 30 in 12 months. Late or thin returns can cancel the arrangement — then full PAYE for every visitor.
EP Appendix 8, NT codes and ERS
Appendix 4 excludes non-treaty residents and staff of overseas branches of UK companies. EP Appendix 8 can cut the burden: one annual RTI submission and tax payment by 31 May. Conditions are tight — generally ≤ 60 workdays (different day count), cannot use Appendix 4, no NIC liability, no taxable benefits. Nil returns still required. Small populations can sometimes use individual NT codes instead of full Appendix 4.
Share plans still need thought. Non-tax-advantaged ERS reporting has been eased for Appendix 4 visitors where no UK IT/NIC is due, but residual UK history or taxable events can put you back into ERS reporting — see also ERS Bulletin 66.
NIC is not the treaty
Double tax treaties do not govern National Insurance. Social security agreements do — EU/EEA/Swiss/Gibraltar rules, reciprocal agreements, or pure UK domestic law.
- Detached workers from agreement countries can often stay on home social security for temporary UK work (commonly up to two years under EU-style rules), evidenced by an A1/certificate of coverage. Keep it.
- Replacements, uninsured home status, or a suspended home contract with local UK employment can flip the worker onto UK NIC from day one — and the domestic 52-week exemption in Reg 145(2) may not apply when an agreement puts them under UK legislation.
- Multi-state workers can be UK-liable even with limited UK days.
- From non-agreement countries, Reg 145(2) can give a 52-week Class 1 exemption if the worker is not ordinarily resident/employed in the UK, usually works abroad for a foreign employer, and is here only temporarily. Fail any limb and NIC runs from day one.
- Secondary contributor rules still matter where the legal employer has no UK place of business — NIM33730. Use a NIC-only PAYE scheme where Income Tax is out but NIC is in.
Appendix 4 does not cover NIC. Appendix 8 excludes anyone with a NIC liability. Run the two analyses separately every time.
HMRC’s common-error list
Part 4 is your audit programme. HMRC keeps seeing: no real inbound tracker; weak records behind “no PAYE/no NIC” calls; assuming short-term means no PAYE; failing to check the right version of the right treaty; undercounting days (weekends, leave, arrival/departure); ignoring recharges and ultimate cost bearing; treating overseas branches as separate employers; misreading the 60-day rule; late or incomplete Appendix 4 returns; stuffing non-resident directors into Appendix 4/8; assuming NIC follows Income Tax.
Interest and penalties attach. Checks escalate where systems are poor or treaty conditions fail while PAYE was never operated. Keep PAYE records at least three years after the tax year — contracts, duty notes, day logs with travel evidence, expenses, bonuses, share awards, benefits and NIC certificates. See HMRC’s compliance checks factsheet.
What every CFO should lock this month
- Owner. One accountable owner across tax, payroll and mobility.
- Population. Map assignees, travellers, project crews, multi-state commuters and parent-company “two-week helpers”.
- Tracker. Produce treaty days and workdays, with 30-day intermittent escalation.
- Arrangements. Confirm live EP Appendix 4/8 status; diary 31 May; purge wrongly included branch staff.
- Economic employer / recharge. Align contracts, supervision reality and “ultimately borne” analysis.
- NIC stack. Separate playbooks for A1s, reciprocal agreements and Reg 145(2). Certificate on file before first UK payday where relied on.
- Host PAYE risk. If the overseas legal employer has no UK presence, check whether the UK host must operate PAYE.
- Evidence pack. If you cannot prove the decision in 48 hours, you do not have a control.
- Directors and ERS. Keep non-resident directors out of the wrong appendices; reconcile awards to ERS.
- Audit committee one-pager. Residual risk, arrangement status, last 31 May quality, untracked cohorts.
Bottom line
GfC19 does not invent new tax. It documents how HMRC expects you to run a process most groups still under-invest in. Treaty relief is not a PAYE off-switch. NIC is not a treaty problem. Branches are not subsidiaries. Day counts include the weekend you stayed in town. Appendix 4 and 8 are valuable — until a late annual report or a bad economic-employer fact pattern collapses them.
If international people move through your UK perimeter, read GfC19, pressure-test your tracker before the next travel peak, and put 31 May EP reporting on the same calendar as CT and ERS. Cheaper than discovering your “few days in London” programme in a compliance check.
Mark Hendy is a PE-facing CFO and tax agent. This note is practical commentary on published HMRC material, not advice on any specific visitor population. Check the treaty, the social security agreement and the facts.