diff --git a/libs/ardour/tempo.cc b/libs/ardour/tempo.cc
index 3738992479..3865fe3e19 100644
--- a/libs/ardour/tempo.cc
+++ b/libs/ardour/tempo.cc
@@ -4288,6 +4288,10 @@ TempoMap::tempo_section_at_beat_locked (const Metrics& metrics, const double& be
 TempoSection*
 TempoMap::next_tempo_section (TempoSection* ts) const
 {
+	if (!ts) {
+		return 0;
+	}
+
 	Glib::Threads::RWLock::ReaderLock lm (lock);
 
 	TempoSection* prev = 0;