diff --git a/vumi/blinkenlights/metrics.py b/vumi/blinkenlights/metrics.py
index dc3bf61fc..00437bbe3 100644
--- a/vumi/blinkenlights/metrics.py
+++ b/vumi/blinkenlights/metrics.py
@@ -79,24 +79,24 @@ def stop(self):
             self._task.stop()
             self._task = None
 
-    def publish_metrics(self, publisher=None):
+    def publish_metrics(self):
         """
         Publish all waiting metrics.
-
-        If a publisher is provided, it will be used instead of the manager's
-        publisher.
         """
         msg = MetricMessage()
         self._collect_oneshot_metrics(msg)
         self._collect_polled_metrics(msg)
-        if publisher is None:
-            publisher = self._publisher
-        publisher.publish_message(msg)
+        self.publish_message(msg)
         if self._on_publish is not None:
             self._on_publish(self)
 
     _publish_metrics = publish_metrics  # For old tests that poke this.
 
+    def publish_message(self, msg):
+        if self._publisher is None:
+            raise ValueError("No publisher available.")
+        self._publisher.publish_message(msg)
+
     def _collect_oneshot_metrics(self, msg):
         oneshots, self._oneshot_msgs = self._oneshot_msgs, []
         for metric, values in oneshots:
diff --git a/vumi/blinkenlights/tests/test_metrics.py b/vumi/blinkenlights/tests/test_metrics.py
index 2388a7a6d..db29382fa 100644
--- a/vumi/blinkenlights/tests/test_metrics.py
+++ b/vumi/blinkenlights/tests/test_metrics.py
@@ -114,7 +114,7 @@ def test_start_manager_no_publisher_no_channel(self):
         mm = metrics.MetricManager("vumi.test.")
         self.assertEqual(mm._publisher, None)
         self.assertEqual(mm._task, None)
-        self.assertRaises(Exception, mm.start)
+        self.assertRaises(RuntimeError, mm.start)
 
     @inlineCallbacks
     def test_start_manager_publisher_and_channel(self):
@@ -123,7 +123,7 @@ def test_start_manager_publisher_and_channel(self):
         self.assertEqual(mm._publisher, publisher)
         self.assertEqual(mm._task, None)
         channel = yield get_stubbed_channel(self.worker_helper.broker)
-        self.assertRaises(Exception, mm.start, channel)
+        self.assertRaises(RuntimeError, mm.start, channel)
 
     def test_start_manager_publisher_no_channel(self):
         publisher = metrics.MetricPublisher()
@@ -218,22 +218,7 @@ def test_publish_metrics_not_started_no_publisher(self):
         mm = metrics.MetricManager("vumi.test.")
         self.assertEqual(mm._publisher, None)
         mm.oneshot(metrics.Count("my.count"), 1)
-        self.assertRaises(Exception, mm.publish_metrics)
-
-    @inlineCallbacks
-    def test_publish_metrics_not_started_with_publisher(self):
-        mm = metrics.MetricManager("vumi.test.", 0.1, self.on_publish)
-        publisher = metrics.MetricPublisher()
-        channel = yield get_stubbed_channel(self.worker_helper.broker)
-        publisher.start(channel)
-        cnt = metrics.Count("my.count")
-
-        self.assertEqual(mm._publisher, None)
-        mm.oneshot(cnt, 1)
-        self.assertEqual(len(mm._oneshot_msgs), 1)
-        mm.publish_metrics(publisher)
-        self.assertEqual(mm._oneshot_msgs, [])
-        self._check_msg(mm, cnt, [1])
+        self.assertRaises(ValueError, mm.publish_metrics)
 
     def test_stop_unstarted(self):
         mm = metrics.MetricManager("vumi.test.", 0.1, self.on_publish)