diff --git a/CONTRIBUTORS.md b/CONTRIBUTORS.md
index 00c6e6edb..be30d1208 100644
--- a/CONTRIBUTORS.md
+++ b/CONTRIBUTORS.md
@@ -34,4 +34,5 @@
 | thomasmelvin        | Thomas Melvin      | Met Office                       | 2026-01-15 |
 | tinyendian          | Wolfgang Hayek     | Earth Sciences New Zealand       | 2026-02-02 |
 | DanStoneMO          | Daniel Stone       | Met Office                       | 2026-02-26 |
-| 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                       | 2026-03-11 |
diff --git a/applications/lfricinputs/fortitude.toml b/applications/lfricinputs/fortitude.toml
new file mode 100644
index 000000000..399f4feb4
--- /dev/null
+++ b/applications/lfricinputs/fortitude.toml
@@ -0,0 +1,11 @@
+##############################################################################
+# (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", "pf"]    #check these file types
+select = ["S101", "PORT011"]
+output-format = "grouped"                #group results by file
+
diff --git a/interfaces/coupled_interface/fortitude.toml b/interfaces/coupled_interface/fortitude.toml
new file mode 100644
index 000000000..d07084eca
--- /dev/null
+++ b/interfaces/coupled_interface/fortitude.toml
@@ -0,0 +1,18 @@
+##############################################################################
+# (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", "pf"]   #check these file types
+
+select = ["S101", "PORT011"]
+
+output-format = "grouped"                #group results by file
+
+[check.per-file-ignores]
+
+"process_send_fields_2d_mod.X90" = ["S101"]
+"set_r_ocean_fraction_mod.F90" = ["S101"]
diff --git a/interfaces/jedi_lfric_interface/fortitude.toml b/interfaces/jedi_lfric_interface/fortitude.toml
new file mode 100644
index 000000000..f8d609bba
--- /dev/null
+++ b/interfaces/jedi_lfric_interface/fortitude.toml
@@ -0,0 +1,18 @@
+##############################################################################
+# (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", "pf"]  #check these file types
+
+select = ["S101", "PORT011"]
+
+output-format = "grouped"                #group results by file
+
+[check.per-file-ignores]
+
+"jedi_lfric_linear_modeldb_driver_mod.f90" = ["S101"]
+"atlas_field_interface_mod.F90" = ["S101"]
diff --git a/interfaces/jules_interface/fortitude.toml b/interfaces/jules_interface/fortitude.toml
new file mode 100644
index 000000000..1dd4c9b7e
--- /dev/null
+++ b/interfaces/jules_interface/fortitude.toml
@@ -0,0 +1,20 @@
+##############################################################################
+# (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", "pf"]   #check these file types
+
+select = ["S101", "PORT011"]
+
+output-format = "grouped"                #group results by file
+
+[check.per-file-ignores]
+
+"update_ancils_alg_mod.x90" = ["S101"]
+"jules_exp_kernel_mod.F90" = ["S101"]
+"jules_extra_kernel_mod.F90" = ["S101"]
+"jules_imp_kernel_mod.F90" = ["S101"]
diff --git a/interfaces/jules_interface/source/algorithm/jules_exp_alg_mod.x90 b/interfaces/jules_interface/source/algorithm/jules_exp_alg_mod.x90
index ee0bb5f8d..971658188 100644
--- a/interfaces/jules_interface/source/algorithm/jules_exp_alg_mod.x90
+++ b/interfaces/jules_interface/source/algorithm/jules_exp_alg_mod.x90
@@ -229,7 +229,7 @@ contains
     integer(tik)         :: id
 
     if ( LPROF ) call start_timing( id, 'jules.explicit' )
- 
+
     call log_event( 'slow_physics: Running explicit JULES layer', LOG_LEVEL_DEBUG )
 
     ! Cannot pass null pointers to invoke calls. Therefore non-pointer variables
diff --git a/interfaces/physics_schemes_interface/fortitude.toml b/interfaces/physics_schemes_interface/fortitude.toml
new file mode 100644
index 000000000..4848b9899
--- /dev/null
+++ b/interfaces/physics_schemes_interface/fortitude.toml
@@ -0,0 +1,13 @@
+##############################################################################
+# (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", "pf"]   #check these file types
+
+select = ["PORT011"]
+
+output-format = "grouped"                #group results by file
diff --git a/interfaces/socrates_interface/fortitude.toml b/interfaces/socrates_interface/fortitude.toml
new file mode 100644
index 000000000..55535500c
--- /dev/null
+++ b/interfaces/socrates_interface/fortitude.toml
@@ -0,0 +1,19 @@
+##############################################################################
+# (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", "pf"]   #check these file types
+
+select = ["S101", "PORT011"]
+
+output-format = "grouped"                #group results by file
+
+[check.per-file-ignores]
+
+"init_radiation_fields_alg_mod.x90" = ["S101"]
+"rad_cloud_alg_mod.x90" = ["S101"]
+"lw_kernel_mod.F90" = ["S101"]
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..3988f89c6
--- /dev/null
+++ b/rose-stem/app/check_fortitude_linter/file/fortitude.toml
@@ -0,0 +1,29 @@
+##############################################################################
+# (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", "pf"]          #check these file types
+
+select = ["S101", "PORT011"]
+
+output-format = "grouped"                #group results by file
+
+
+# "./interfaces/coupled_interface/source/algorithm/process_send_fields_2d_mod.X90" = ["S101"]
+
+# "./interfaces/socrates_interface*" = ["S101"]
+# "../coupled_interface/*" = ["S101"]
+
+
+# "./interfaces/coupled_interface/* = ["S101"]
+
+
+# "../socrates_interface/*" = ["S101"]
+# "physics_schemes_interface/*" = ["S101"]
+# "jules_interface/*" = ["S101"]
+# "jedi_lfric_interface/*" = ["S101"]
+
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..456659c78
--- /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_apps
diff --git a/rose-stem/app/extract_source/bin/extract_source.sh b/rose-stem/app/extract_source/bin/extract_source.sh
index b1297f8f2..9bab6dd06 100755
--- a/rose-stem/app/extract_source/bin/extract_source.sh
+++ b/rose-stem/app/extract_source/bin/extract_source.sh
@@ -7,4 +7,5 @@ cp $SOURCE_ROOT/lfric_apps/dependencies.yaml $CYLC_WORKFLOW_RUN_DIR
 cp $SOURCE_ROOT/SimSys_Scripts/github_scripts/suite_report_git.py $CYLC_WORKFLOW_RUN_DIR/bin
 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/fortitude_linter/fortitude_launcher.py $CYLC_WORKFLOW_RUN_DIR/bin
 cp $SOURCE_DIRECTORY/SimSys_Scripts/github_scripts/get_git_sources.py $CYLC_WORKFLOW_RUN_DIR/bin
diff --git a/rose-stem/site/meto/groups.cylc b/rose-stem/site/meto/groups.cylc
index fa3a62574..2e3efc1cf 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",
         "extract_checker",
         "site_validator",
         "validate_rose_meta",
diff --git a/rose-stem/templates/graph/populate_graph_scripts.cylc b/rose-stem/templates/graph/populate_graph_scripts.cylc
index 41c90a45c..1f70d9baf 100644
--- a/rose-stem/templates/graph/populate_graph_scripts.cylc
+++ b/rose-stem/templates/graph/populate_graph_scripts.cylc
@@ -51,6 +51,7 @@
     {# All other scripts have the same simple graph. These are: #}
     {# * config_dump_checker #}
     {# * style_checker #}
+    {# * fortitude_linter #}
     {# * site_validator #}
     {# * rose-stem_lint_checker #}
     {# * validate_rose_meta #}
diff --git a/rose-stem/templates/runtime/generate_runtime_scripts.cylc b/rose-stem/templates/runtime/generate_runtime_scripts.cylc
index bd602ad7c..a1ce6f61a 100644
--- a/rose-stem/templates/runtime/generate_runtime_scripts.cylc
+++ b/rose-stem/templates/runtime/generate_runtime_scripts.cylc
@@ -43,6 +43,11 @@
         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}}