diff --git a/lib/iris/tests/__init__.py b/lib/iris/tests/__init__.py
index 7b88065d38..c1df4f628b 100644
--- a/lib/iris/tests/__init__.py
+++ b/lib/iris/tests/__init__.py
@@ -39,6 +39,7 @@
 import subprocess
 import sys
 import threading
+from typing import Dict, List
 import unittest
 from unittest import mock
 import warnings
@@ -878,7 +879,9 @@ def check_graphic(self):
         unique_id = self._unique_id()
         repo_fname = os.path.join(_RESULT_PATH, "imagerepo.json")
         with open(repo_fname, "rb") as fi:
-            repo = json.load(codecs.getreader("utf-8")(fi))
+            repo: Dict[str, List[str]] = json.load(
+                codecs.getreader("utf-8")(fi)
+            )
 
         try:
             #: The path where the images generated by the tests should go.
@@ -949,13 +952,16 @@ def _create_missing():
             phash = imagehash.phash(Image.open(buffer), hash_size=_HASH_SIZE)
 
             if unique_id not in repo:
-                if dev_mode:
-                    _create_missing()
-                else:
-                    figure.savefig(result_fname)
-                    emsg = "Missing image test result: {}."
-                    raise AssertionError(emsg.format(unique_id))
-            else:
+                # The unique id might not be fully qualified, e.g.
+                # expects iris.tests.test_quickplot.TestLabels.test_contour.0,
+                # but got test_quickplot.TestLabels.test_contour.0
+                # if we find single partial match from end of the key
+                # then use that, else fall back to the unknown id state.
+                matches = [key for key in repo if key.endswith(unique_id)]
+                if len(matches) == 1:
+                    unique_id = matches[0]
+
+            if unique_id in repo:
                 uris = repo[unique_id]
                 # Extract the hex basename strings from the uris.
                 hexes = [
@@ -984,6 +990,13 @@ def _create_missing():
                         else:
                             emsg = "Image comparison failed: {}"
                             raise AssertionError(emsg.format(msg))
+            else:
+                if dev_mode:
+                    _create_missing()
+                else:
+                    figure.savefig(result_fname)
+                    emsg = "Missing image test result: {}."
+                    raise AssertionError(emsg.format(unique_id))
 
             if _DISPLAY_FIGURES:
                 plt.show()