diff --git a/libs/ardour/ardour/triggerbox.h b/libs/ardour/ardour/triggerbox.h
index 12524be70b..0e90ee1034 100644
--- a/libs/ardour/ardour/triggerbox.h
+++ b/libs/ardour/ardour/triggerbox.h
@@ -244,6 +244,8 @@ class LIBARDOUR_API Trigger : public PBD::Stateful {
 
 	virtual SegmentDescriptor get_segment_descriptor () const = 0;
 
+	static void request_trigger_delete (Trigger* t);
+
   protected:
 	struct UIRequests {
 		std::atomic<bool> stop;
@@ -432,6 +434,7 @@ class LIBARDOUR_API TriggerBoxThread
 	static void init_request_pool() { Request::init_pool(); }
 
 	void set_region (TriggerBox&, uint32_t slot, boost::shared_ptr<Region>);
+	void request_delete_trigger (Trigger* t);
 
 	void summon();
 	void stop();
@@ -443,7 +446,8 @@ class LIBARDOUR_API TriggerBoxThread
 
 	enum RequestType {
 		Quit,
-		SetRegion
+		SetRegion,
+		DeleteTrigger
 	};
 
 	struct Request {
@@ -455,6 +459,8 @@ class LIBARDOUR_API TriggerBoxThread
 		TriggerBox* box;
 		uint32_t slot;
 		boost::shared_ptr<Region> region;
+		/* for DeleteTrigger */
+		Trigger* trigger;
 
 		void* operator new (size_t);
 		void  operator delete (void* ptr, size_t);
@@ -468,6 +474,7 @@ class LIBARDOUR_API TriggerBoxThread
 
 	CrossThreadChannel _xthread;
 	void queue_request (Request*);
+	void delete_trigger (Trigger*);
 };
 
 
@@ -620,6 +627,10 @@ class LIBARDOUR_API TriggerBox : public Processor
 
 		Type type;
 
+		/* cannot use a union here because we need Request to have a
+		 * "trivial" constructor.
+		 */
+
 		TriggerPtr trigger;
 		void* ptr;
 		int32_t slot;
diff --git a/libs/ardour/triggerbox.cc b/libs/ardour/triggerbox.cc
index c66fd95da2..8a1b67df07 100644
--- a/libs/ardour/triggerbox.cc
+++ b/libs/ardour/triggerbox.cc
@@ -110,6 +110,13 @@ Trigger::Trigger (uint32_t n, TriggerBox& b)
 	add_property (_isolated);
 }
 
+void
+Trigger::request_trigger_delete (Trigger* t)
+{
+	std::cerr << "RTD\n";
+	TriggerBox::worker->request_delete_trigger (t);
+}
+
 void
 Trigger::set_pending (Trigger* t)
 {
@@ -2735,7 +2742,7 @@ TriggerBox::set_state (const XMLNode& node, int version)
 			TriggerPtr trig;
 
 			if (_data_type == DataType::AUDIO) {
-				trig = boost::make_shared<AudioTrigger> (all_triggers.size(), *this);
+				trig.reset (new AudioTrigger (all_triggers.size(), *this), Trigger::request_trigger_delete);
 				all_triggers.push_back (trig);
 				trig->set_state (**t, version);
 			} else if (_data_type == DataType::MIDI) {
@@ -2918,6 +2925,9 @@ TriggerBoxThread::thread_work ()
 				case SetRegion:
 					req->box->set_region (req->slot, req->region);
 					break;
+				case DeleteTrigger:
+					delete_trigger (req->trigger);
+					break;
 				default:
 					break;
 				}
@@ -2976,3 +2986,19 @@ TriggerBoxThread::set_region (TriggerBox& box, uint32_t slot, boost::shared_ptr<
 
 	queue_request (req);
 }
+
+void
+TriggerBoxThread::request_delete_trigger (Trigger* t)
+{
+	std::cerr << "RDT\n";
+	TriggerBoxThread::Request* req = new TriggerBoxThread::Request (DeleteTrigger);
+	req->trigger  = t;
+	queue_request (req);
+}
+
+void
+TriggerBoxThread::delete_trigger (Trigger* t)
+{
+	std::cerr << "trigger delete for " << t << endl;
+	delete t;
+}