$re = '/.*\s(\d{11}|\d{5}\s\d{3}\s\d{3}|\d{5}\s\d{6}|\d{14}|\+\d{12}|\+\d{3}\s\d{3}\s\d{3}\s\d{3}|\d{4}\s\d{3}\s\d{3})\s.*/m';
$str = 'fdsgf dsgfd ggfs s 07123452670 ar gs fgsdf gsdf
t hth rt hrth rth 07812 345 931 tr yrt rty
try erty tr ytr y 07412 123466 tr yert y
tery ert y 00447912345188 etry ert y
tery etr yrt yret +971557017442 ert yert yrety
et yetr yertytr ety ert y +971 557 856 832 etry rt ytr y
etr yerty etry erty 0414 934 993 erty etry etry';
$subst = "$1";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
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