UK Phone Number Validation Regex

Validate UK phone numbers including mobile numbers starting with 07 and international format +44 using regex patterns.

Pattern Breakdown

^(\+44\s?7\d{3}|\(?07\d{3}\)?)\s?\d{3}\s?\d{3}$

Components

Detailed Breakdown

• (\+44\s?7\d{3}\|\(?07\d{3}\)?) - Alternation group:
  • \+44\s?7\d{3} - International format: +44 (optional space) + 7 + 3 digits
  • \| - OR operator
  • \(?07\d{3}\)? - UK format: optional (, 07, 3 digits, optional )
• \s? - Optional space separator
• \d{3} - Three digits
• \s? - Optional space separator
• \d{3} - Three digits

Examples

Valid:

• +44 7123 456789
• +447123456789
• 07123 456789
• (07123) 456789
• 07123456789
• +44 7123 456 789

Invalid:

• 0712345678 (missing digit - should be 11 digits total)
• 06123456789 (doesn't start with 07 or +44)
• +44 8123 456789 (doesn't start with 7 after +44)
• 07123-456789 (dashes not supported, only spaces)
• +44 7123 45678 (too short)

Implementation

JavaScript

const ukPhoneRegex = /^(\+44\s?7\d{3}|\(?07\d{3}\)?)\s?\d{3}\s?\d{3}$/;
ukPhoneRegex.test('+44 7123 456789'); // true
ukPhoneRegex.test('07123456789'); // true
ukPhoneRegex.test('(07123) 456789'); // true
ukPhoneRegex.test('06123456789'); // false (wrong prefix)

Python

import re
uk_phone_regex = r'^(\+44\s?7\d{3}|\(?07\d{3}\)?)\s?\d{3}\s?\d{3}$'
bool(re.match(uk_phone_regex, '+44 7123 456789'))  # True
bool(re.match(uk_phone_regex, '07123456789'))  # True
bool(re.match(uk_phone_regex, '06123456789'))  # False

Go

ukPhoneRegex := regexp.MustCompile(`^(\+44\s?7\d{3}|\(?07\d{3}\)?)\s?\d{3}\s?\d{3}$`)
ukPhoneRegex.MatchString("+44 7123 456789") // true
ukPhoneRegex.MatchString("07123456789") // true
ukPhoneRegex.MatchString("06123456789") // false

Limitations

1. Mobile numbers only: This pattern specifically targets UK mobile numbers (07xxx)
2. No landline support: Doesn't validate UK landline numbers
3. No area code validation: Doesn't verify if mobile prefix is valid
4. Limited formatting: Only supports spaces, not dashes or dots
5. Fixed length: Assumes 11-digit UK mobile format

When to Use

• UK mobile number validation
• Applications targeting UK users
• When you need to accept both +44 and 07 formats
• Quick format checking for UK mobiles

For production, consider:

• Adding landline number support
• Using libphonenumber library for comprehensive validation
• Validating mobile prefixes against known ranges
• Supporting additional formatting options
• Normalizing to E.164 format for storage