diff --git a/Testing/SystemTests/tests/analysis/ISIS_PowderPolarisTest.py b/Testing/SystemTests/tests/analysis/ISIS_PowderPolarisTest.py
index 02db506284bbfbe5ab86a395f48feebd40afa6cf..01f7ae6793046d6a035882734fb06f87796ec0e9 100644
--- a/Testing/SystemTests/tests/analysis/ISIS_PowderPolarisTest.py
+++ b/Testing/SystemTests/tests/analysis/ISIS_PowderPolarisTest.py
@@ -72,7 +72,7 @@ class FocusTest(stresstesting.MantidStressTest):
 
     focus_results = None
     existing_config = config['datasearch.directories']
-    self.tolerance = 1e-13
+    tolerance = 1e-13
 
     def requiredFiles(self):
         return _gen_required_files()