$re = '/(?:[^\d\+]|^)(0(?:[27][3-9]|4\d)\d{7})(?:\D|$)/m';
$str = 'Bad:
+0010293991
0110293999
02102939991
091029399
Good:
0236789652
0470982761
0780817211';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php