diff --git a/tests/wapi_adapter.py b/tests/wapi_adapter.py
index 7f73187..0f9915f 100644
--- a/tests/wapi_adapter.py
+++ b/tests/wapi_adapter.py
@@ -16,6 +16,7 @@
 """
 
 import os
+from http import HTTPStatus
 from multiprocessing import Lock
 from pickle import Pickler, Unpickler
 from typing import Any
@@ -385,4 +386,4 @@ def realise_outputs(
     ) -> tuple[dict[str, Any], int]:
         del running_workflow_step_id
         del outputs
-        return {}, 0
+        return {}, HTTPStatus.OK
diff --git a/workflow/workflow_engine.py b/workflow/workflow_engine.py
index 85f57b4..e1061cc 100644
--- a/workflow/workflow_engine.py
+++ b/workflow/workflow_engine.py
@@ -24,6 +24,7 @@
 
 import logging
 import sys
+from http import HTTPStatus
 from typing import Any, Dict, Optional
 
 from decoder.decoder import TextEncoding, decode
@@ -259,26 +260,40 @@ def _handle_pod_message(self, msg: PodMessage) -> None:
         # Project directory, while also marking the Step as DONE (successfully).
         # We pass the outputs to the DM via a call to the API adapter's realise_outputs().
         # In return it copies (links) these files to the Project directory.
-        #
-        # We then inspect the Workflow to determine the next step.
-
         wfid = rwf_response["workflow"]["id"]
         assert wfid
         wf_response, _ = self._wapi_adapter.get_workflow(workflow_id=wfid)
         _LOGGER.debug("API.get_workflow(%s) returned: -\n%s", wfid, str(wf_response))
 
+        error_num: int | None = None
+        error_msg: str | None = None
         if output_values := get_workflow_output_values_for_step(wf_response, step_name):
             # Got some output values
             # Inform the DM so it can link them to the Project directory
-            self._wapi_adapter.realise_outputs(
+            response, status_code = self._wapi_adapter.realise_outputs(
                 running_workflow_step_id=r_wfsid,
                 outputs=output_values,
             )
+            if status_code != HTTPStatus.OK:
+                error_num = status_code
+                error_msg = (
+                    response["error"]
+                    if "error" in response
+                    else "Undisclosed error when realising outputs"
+                )
 
-        # Now we can mark this step as DONE...
+        if error_num is not None:
+            # The job was successful but linking outputs (back to the Project directory)
+            # appears to have failed.
+            self._set_step_error(step_name, r_wfid, r_wfsid, error_num, error_msg)
+            return
+
+        # We then inspect the Workflow to determine the next step.
         self._wapi_adapter.set_running_workflow_step_done(
             running_workflow_step_id=r_wfsid,
-            success=True,
+            success=error_num is None,
+            error_num=error_num,
+            error_msg=error_msg,
         )
 
         # We have the step from the Instance that's just finished,