diff --git a/CONTRIBUTORS.md b/CONTRIBUTORS.md
index 8fbcb1c91..330823d6e 100644
--- a/CONTRIBUTORS.md
+++ b/CONTRIBUTORS.md
@@ -22,4 +22,5 @@
 | MetBenjaminWent  | Benjamin Went          | Met Office  | 2026-01-30 |
 | jcsmeto          | James Cunningham-Smith | Met Office  | 2026-02-06 |
 | thomasmelvin     | Thomas Melvin          | Met Office  | 2026-01-15 |
-| ericaneininger   | Erica Neininger        | Met Office  | 2026-03-02 |
\ No newline at end of file
+| ericaneininger   | Erica Neininger        | Met Office  | 2026-03-02 |
+| mo-lucy-gordon   | Lucy Gordon            | Met Office  | 2026-03-18 |
\ No newline at end of file
diff --git a/infrastructure/fortitude.toml b/infrastructure/fortitude.toml
new file mode 100644
index 000000000..2019891b4
--- /dev/null
+++ b/infrastructure/fortitude.toml
@@ -0,0 +1,14 @@
+##############################################################################
+# (c) Crown copyright Met Office. All rights reserved.
+# The file LICENCE, distributed with this code, contains details of the terms
+# under which the code may be used.
+##############################################################################
+
+[check]
+
+file-extensions= ["f90", "F90", "X90", "x90"]          #check these file types
+
+
+select = ["C121"]
+
+output-format = "grouped"                #group results by file
diff --git a/rose-stem/app/check_fortitude_linter/file/fortitude.toml b/rose-stem/app/check_fortitude_linter/file/fortitude.toml
new file mode 100644
index 000000000..577dcd310
--- /dev/null
+++ b/rose-stem/app/check_fortitude_linter/file/fortitude.toml
@@ -0,0 +1,15 @@
+##############################################################################
+# (c) Crown copyright Met Office. All rights reserved.
+# The file LICENCE, distributed with this code, contains details of the terms
+# under which the code may be used.
+##############################################################################
+
+[check]
+
+file-extensions= ["f90", "F90", "X90",  "x90"]          #check these file types
+
+
+select = ["C121"]
+
+
+output-format = "grouped"                #group results by file
diff --git a/rose-stem/app/check_fortitude_linter/rose-app.conf b/rose-stem/app/check_fortitude_linter/rose-app.conf
new file mode 100644
index 000000000..4fb874d41
--- /dev/null
+++ b/rose-stem/app/check_fortitude_linter/rose-app.conf
@@ -0,0 +1,2 @@
+[command]
+default=$CYLC_WORKFLOW_RUN_DIR/bin/fortitude_launcher.py $SOURCE_ROOT/lfric_core
diff --git a/rose-stem/site/meto/groups.cylc b/rose-stem/site/meto/groups.cylc
index 2452ddd76..62646ad80 100644
--- a/rose-stem/site/meto/groups.cylc
+++ b/rose-stem/site/meto/groups.cylc
@@ -9,6 +9,7 @@
     "scripts": [
         "config_dump_checker",
         "style_checker",
+        "fortitude_linter",
         "site_validator",
         "validate_rose_meta",
         "rose-stem_lint_checker",
diff --git a/rose-stem/templates/graph/populate_graph_scripts.cylc b/rose-stem/templates/graph/populate_graph_scripts.cylc
index 25e0eeda1..2aa328729 100644
--- a/rose-stem/templates/graph/populate_graph_scripts.cylc
+++ b/rose-stem/templates/graph/populate_graph_scripts.cylc
@@ -51,6 +51,7 @@
     {# * config_dump_checker #}
     {# * style_checker #}
     {# * site_validator #}
+    {# * fortitude_linter #}
     {# * rose-stem_lint_checker #}
     {# * validate_rose_meta #}
     {# * global_variables_checker #}
diff --git a/rose-stem/templates/runtime/generate_runtime_control.cylc b/rose-stem/templates/runtime/generate_runtime_control.cylc
index d69b6be46..4fe249c65 100644
--- a/rose-stem/templates/runtime/generate_runtime_control.cylc
+++ b/rose-stem/templates/runtime/generate_runtime_control.cylc
@@ -25,6 +25,7 @@
                       cp $SOURCE_ROOT/SimSys_Scripts/github_scripts/suite_data.py $CYLC_WORKFLOW_RUN_DIR/bin
                       cp $SOURCE_ROOT/SimSys_Scripts/github_scripts/git_bdiff.py $CYLC_WORKFLOW_RUN_DIR/bin
                       cp $SOURCE_ROOT/SimSys_Scripts/github_scripts/get_git_sources.py $CYLC_WORKFLOW_RUN_DIR/bin
+                      cp $SOURCE_ROOT/SimSys_Scripts/fortitude_linter/fortitude_launcher.py $CYLC_WORKFLOW_RUN_DIR/bin
                       """
         [[[environment]]]
             SOURCE_DIRECTORY = $SOURCE_ROOT
diff --git a/rose-stem/templates/runtime/generate_runtime_scripts.cylc b/rose-stem/templates/runtime/generate_runtime_scripts.cylc
index 02faaf7b2..3c501f06f 100644
--- a/rose-stem/templates/runtime/generate_runtime_scripts.cylc
+++ b/rose-stem/templates/runtime/generate_runtime_scripts.cylc
@@ -36,6 +36,11 @@
         inherit={{inherit.str|upper}}
         script="rose task-run --app-key=check_style"
 
+{% elif "fortitude_linter" in task %}
+
+        inherit={{inherit.str|upper}}
+        script="rose task-run --app-key=check_fortitude_linter"
+
 {% elif "extract_checker" in task %}
 
         inherit={{inherit.str|upper}}