UK UTR (Unique Taxpayer Reference) Regex for PHP

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching uk utr (unique taxpayer reference), ported and verified for PHP. Financial data validation has zero tolerance for false negatives — a missed invalid entry can corrupt downstream calculations. The snippet below is ready to drop into your PHP project — whether you're validating in a Laravel validator, a WordPress plugin, or a standalone PHP script.

Php Implementation

<?php
// UK UTR (Unique Taxpayer Reference)
// ReDoS-safe | RegexVault — Finance > Tax & Registration

define('UK_UTR_UNIQUE_TAXPAYER_REFERENCE_PATTERN', '/^[0-9]{10}$/');

function validate_uk_utr_unique_taxpayer_reference(string $input): bool {
    return (bool) preg_match(UK_UTR_UNIQUE_TAXPAYER_REFERENCE_PATTERN, $input);
}

// Example
var_dump(validate_uk_utr_unique_taxpayer_reference("1234567890")); // bool(true)

Test Cases

When to use this pattern

This pattern is drawn from the Finance > Tax & Registration category and carries a ReDoS-safe certification. That matters for PHP developers because especially relevant in PHP where PCRE backtracking limits can trigger silent failures on malicious input. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

Issued by HMRC to individuals and companies for self assessment. Personal UTR and company UTR are both 10 digits but used in different contexts. The first digit of a company UTR indicates the type (0-9).