Why is CakePHP inserting a space before my xml layout?

I am having a really frustrating problem in CakePHP where a space keeps coming up at the beginning of my KML file layout which causes Google Earth to reject the KML file!

<?php header("Content-disposition: attachment; filename=area.kml");
header("Content-Type: application/vnd.google-earth.kml+xml kml; charset=utf8");
header("Content-Transfer-Encoding: binary");
header("Pragma: no-cache");
header("Expires: 0");
echo '<?xml version="1.0" encoding="UTF-8"?>';

    	<?php echo $content_for_layout ?>

for the output I get

" <?xml version="1.0" encoding="UTF-8"?>"

ect ect
please help!