UK UTR (Unique Taxpayer Reference) Regex for Python

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching uk utr (unique taxpayer reference), ported and verified for Python. 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 Python project — whether you're validating in a Django view, a FastAPI endpoint, or a standalone data processing script.

Python Implementation

# UK UTR (Unique Taxpayer Reference)
# ReDoS-safe | RegexVault — Finance > Tax & Registration

import re

uk_utr_unique_taxpayer_reference_pattern = re.compile(r'^[0-9]{10}$')

def validate_uk_utr_unique_taxpayer_reference(value: str) -> bool:
    return bool(uk_utr_unique_taxpayer_reference_pattern.fullmatch(value))

# Example
print(validate_uk_utr_unique_taxpayer_reference("1234567890"))  # 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 Python developers because particularly important in Python web servers where CPU-bound regex operations can stall concurrent request handling. 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).