Isolate just the area identifier from a UK postcode. So 'BA6 5TY' would result in 'BA' and 'N5 7TY' would result in 'N'

identify_uk_postcode_area.php

<?php
// Define postcode
$postcode = "BA6 5TY";
// Isolate first two characters of the postcode and replace any integer with nothing
$postcode_area = preg_replace("/[0-9]/","",substr($postcode, 0, 2));