diff --git a/custom_components/span_panel/lock.py b/custom_components/span_panel/lock.py
index 2bc99963..877b243f 100644
--- a/custom_components/span_panel/lock.py
+++ b/custom_components/span_panel/lock.py
@@ -133,11 +133,17 @@ def _apply(self, evse: SpanEvseSnapshot) -> None:
 
     @property
     def available(self) -> bool:
-        """False while the panel is offline: a control that cannot reach the panel is not a control."""
+        """False while the panel is offline, or the charger no longer offers its lock.
+
+        A control that cannot reach the panel is not a control, and neither is one
+        whose charger has left the snapshot or stopped declaring the lock settable.
+        """
         if not self._transport_available:
             return False
         if self.coordinator.panel_offline:
             return False
+        if self._evse().lock_control is None:
+            return False
         return super().available
 
     async def async_lock(self, **kwargs: Any) -> None:
diff --git a/tests/test_evse_lock.py b/tests/test_evse_lock.py
index ed4816fb..2d0b46a6 100644
--- a/tests/test_evse_lock.py
+++ b/tests/test_evse_lock.py
@@ -126,3 +126,22 @@ async def test_the_lock_is_unavailable_while_the_panel_is_offline(hass: HomeAssi
     lock.coordinator.panel_offline = True
 
     assert lock.available is False
+
+
+@pytest.mark.parametrize("withdrawn", ["charger_gone", "lock_not_settable"])
+async def test_the_lock_is_withdrawn_when_the_charger_stops_offering_it(
+    hass: HomeAssistant, withdrawn: str
+) -> None:
+    snapshot = _snapshot()
+    (lock,) = await _created(hass, snapshot)
+    lock.coordinator.panel_offline = False
+    assert lock.available is True
+
+    evse = dict(snapshot.evse)
+    if withdrawn == "charger_gone":
+        del evse[SETTABLE]
+    else:
+        evse[SETTABLE] = replace(evse[SETTABLE], lock_control=None)
+    lock.coordinator.data = replace(snapshot, evse=evse)
+
+    assert lock.available is False