diff --git a/integration/100_launch_test.sh b/integration/100_launch_test.sh
index 8dbc1c22a..748a6de21 100755
--- a/integration/100_launch_test.sh
+++ b/integration/100_launch_test.sh
@@ -13,4 +13,8 @@ wait_for_containers "$HOST1" 60 weave weavescope
 has_container "$HOST1" weave
 has_container "$HOST1" weavescope
 
+# Fail if the top-level UI is suspiciously small
+ui_len="$(curl -s "http://$HOST1:4040/" | wc -c)"
+assert_raises "(( $ui_len > 500 ))" 0
+
 scope_end_suite