Do not use '+44' at the start of telephone numbers.
Over 60% of our web visitors are based in the UK so including '+44' is unnecessary. Including '+44 (0)' at the start of a phone number can be distracting and increase cognitive load for the user.
Include a space between city and local exchange. Include a space in the middle of the last 6 digits. Format mobile numbers in the same way: 5 digits, a space, 3 digits, a space, 3 digits.
Always format telephone numbers as clickable links.
At least 40% of our users are accessing the site on mobile phones. Making telephone numbers clickable links helps them to call the number.