diff --git a/libs/ardour/ardour/slavable_automation_control.h b/libs/ardour/ardour/slavable_automation_control.h
index 9cc1442bfb..17aafd699a 100644
--- a/libs/ardour/ardour/slavable_automation_control.h
+++ b/libs/ardour/ardour/slavable_automation_control.h
@@ -69,8 +69,6 @@ public:
 	*/
 	int32_t   get_boolean_masters () const;
 
-	std::vector<PBD::ID> masters () const;
-
 	PBD::Signal0<void> MasterStatusChange;
 
 	void use_saved_master_ratios ();