diff --git a/phpBB/phpbb/di/extension/config.php b/phpBB/phpbb/di/extension/config.php
index 5fcb2d6f10..2603e7b358 100644
--- a/phpBB/phpbb/di/extension/config.php
+++ b/phpBB/phpbb/di/extension/config.php
@@ -70,7 +70,7 @@ class config extends Extension
 	{
 		if (preg_match('#^[a-z]+$#', $acm_type))
 		{
-			return '\\phpbb\cache\driver\\'.$acm_type;
+			return 'phpbb\\cache\\driver\\' . $acm_type;
 		}
 
 		return $acm_type;