[twitter-dev] XML feed not loading as before - PHP

$twitter_url = "http://api.twitter.com/1/statuses/user_timeline/
britishabroad.xml";

$buffer = file_get_contents($twitter_url);
$xml = new SimpleXMLElement($buffer);

$status_item = $xml -> status;
$status =  $status_item -> text;

echo $status;

I am getting an error:

Fatal error: Uncaught exception 'Exception' with message 'String could
not be parsed as XML' in /home/bhammers/demophon/dashboard/test.php:5
Stack trace: #0 /home/bhammers/demophon/dashboard/test.php(5):
SimpleXMLElement->__construct('') #1 {main} thrown in /home/bhammers/
demophon/dashboard/test.php on line 5


Would appreciate any help.

Thanks

Colin