diff --git a/modules/Bio/EnsEMBL/Intron.pm b/modules/Bio/EnsEMBL/Intron.pm
index 3605757d3d7898c6ab5ccde517d5c4d3e1154ffb..4e76ac25488bddce89d4e60f99a4f3167ffb51dc 100644
--- a/modules/Bio/EnsEMBL/Intron.pm
+++ b/modules/Bio/EnsEMBL/Intron.pm
@@ -56,7 +56,7 @@ use Bio::EnsEMBL::Utils::Argument qw( rearrange );
 sub new {
   my ( $proto, $e1, $e2 ) = @_;
 
-  $class = ref $class || $proto;
+  my $class = ref $proto || $proto;
 
   my $self = $class->SUPER::new();