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Country guide · United Kingdom

Get an ITIN as a British citizen

Last updated: August 2026

Bottom line

Get an ITIN as a British citizen is straightforward once the United Kingdom paperwork is in order. As a Hague Convention member, United Kingdom issues a single apostille that the US recognizes without further legalization. Treaty status (for ITIN holders): Active US treaty available, use Form W-8BEN to claim reduced withholding once the ITIN is assigned.

HMRC is comfortable with US LLCs but specific guidance on the disregarded-entity treatment is uneven across HMRC officers. Keep clean records. This is the country-specific guide for British citizens to get an itin, apostille, banking, and treaty notes that change by jurisdiction. For the canonical procedural sequence (the steps everyone follows regardless of citizenship), see the main ITIN application page.

An ITIN (Individual Taxpayer Identification Number) is the IRS-issued tax ID for non-US residents without an SSN. It unlocks US tax filings, US bank accounts at issuers that require a TIN, and, most importantly for digital nomads, a US credit file. The application is Form W-7 + a valid reason code + original ID documents. Wrong reason code is the #1 cause of rejection.

What British citizens need to apply for an ITIN

Apostille

FCDO Legalisation Office (Milton Keynes)

~1·2 weeks, ~USD 40. As a Hague Convention member, United Kingdom issues a single apostille that the US recognizes without further legalization.

Banking flow

UK residents open Mercury remotely with passport + proof of UK address. GBP outbound from Mercury via Wise to Monzo/Starling is the standard flow.

Timezone

UTC+0 (GMT), 5 hours ahead of IRS Austin. IRS Austin is on UTC-6 / Asunción Migración on UTC-3.

Country-specific note

Common: UK creators and SaaS founders selling to US customers who need an ITIN for Form 1040-NR filings + Mercury onboarding.

Treaty status (for ITIN holders): Active US treaty available, use Form W-8BEN to claim reduced withholding once the ITIN is assigned.

Questions British citizens ask about itin application

How long does the apostille take for British citizens? +

1·2 weeks through FCDO Legalisation Office (Milton Keynes), at roughly USD 40. As a Hague Convention member, United Kingdom issues a single apostille that the US recognizes without further legalization.

How do British-resident clients usually handle banking with their US LLC? +

UK residents open Mercury remotely with passport + proof of UK address. GBP outbound from Mercury via Wise to Monzo/Starling is the standard flow.

What is the most common reason British citizens apply for an ITIN? +

Common: UK creators and SaaS founders selling to US customers who need an ITIN for Form 1040-NR filings + Mercury onboarding.

Apply for your ITIN, British citizen

See the full procedural sequence on the canonical ITIN application page, or jump straight to the apply form.

Apply for your ITIN
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