diff --git a/libs/core/src/ecflow/core/Environment.hpp b/libs/core/src/ecflow/core/Environment.hpp
index 63e982dca..77ba9bda0 100644
--- a/libs/core/src/ecflow/core/Environment.hpp
+++ b/libs/core/src/ecflow/core/Environment.hpp
@@ -60,6 +60,10 @@ constexpr const char* ECF_USER = "ECF_USER";
 constexpr const char* ECF_DEBUG_CLIENT = "ECF_DEBUG_CLIENT";
 constexpr const char* ECF_DEBUG_LEVEL  = "ECF_DEBUG_LEVEL";
 
+// Mirror kill-switches
+constexpr const char* ECF_MIRROR_DISABLE         = "ECF_MIRROR_DISABLE";
+constexpr const char* ECF_MIRROR_DISABLE_QUERIES = "ECF_MIRROR_DISABLE_QUERIES";
+
 namespace /* anonymous */ {
 
 template <typename T>
diff --git a/libs/node/src/ecflow/node/MirrorAttr.cpp b/libs/node/src/ecflow/node/MirrorAttr.cpp
index c0eff298a..4ad6a6ac9 100644
--- a/libs/node/src/ecflow/node/MirrorAttr.cpp
+++ b/libs/node/src/ecflow/node/MirrorAttr.cpp
@@ -13,6 +13,7 @@
 #include <sstream>
 
 #include "ecflow/core/Ecf.hpp"
+#include "ecflow/core/Environment.hpp"
 #include "ecflow/core/Message.hpp"
 #include "ecflow/core/Overload.hpp"
 #include "ecflow/core/exceptions/Exceptions.hpp"
@@ -90,6 +91,16 @@ void MirrorAttr::finish() {
 void MirrorAttr::mirror() {
     SLOG(D, "MirrorAttr: poll Mirror attribute '" << absolute_name() << "'");
 
+    // Check if local mirrors are disabled via ECF_MIRROR_DISABLE variable
+    if (parent_) {
+        std::string disable_mirrors;
+        if (parent_->findParentVariableValue(ecf::environment::ECF_MIRROR_DISABLE, disable_mirrors)) {
+            // ECF_MIRROR_DISABLE is defined and non-empty; skip mirror polling
+            SLOG(D, "MirrorAttr: Mirror attribute '" << absolute_name() << "' disabled via ECF_MIRROR_DISABLE");
+            return;
+        }
+    }
+
     start_controller();
     if (!controller_) {
         return; // Can't continue without a running controller...
diff --git a/libs/node/test/parser/TestMirrorAttr.cpp b/libs/node/test/parser/TestMirrorAttr.cpp
index 02802640d..c4d487a36 100644
--- a/libs/node/test/parser/TestMirrorAttr.cpp
+++ b/libs/node/test/parser/TestMirrorAttr.cpp
@@ -106,6 +106,51 @@ BOOST_AUTO_TEST_CASE(can_parse_mirror_attribute_on_task_with_all_attributes) {
     BOOST_CHECK_EQUAL(mirror.ssl(), true);
 }
 
+BOOST_AUTO_TEST_CASE(mirror_disabled_when_ECF_MIRROR_DISABLE_is_set) {
+    ECF_NAME_THIS_TEST();
+
+    using namespace ecf;
+
+    std::string definition = R"(
+        suite s1
+          edit ECF_MIRROR_DISABLE "yes"
+          family f1
+            task t1
+              mirror --name A --remote_path /s1/f1/t2 --remote_host invalid-host --remote_port 9999 --polling 1
+          endfamily
+    )";
+
+    Defs defs;
+    DefsStructureParser parser(&defs, definition, true);
+
+    std::string errorMsg, warningMsg;
+    bool parsedOK = parser.doParse(errorMsg, warningMsg);
+    BOOST_CHECK_MESSAGE(parsedOK, "Failed to parse definition: " << errorMsg);
+
+    const auto& suites = defs.suiteVec();
+    BOOST_CHECK_EQUAL(suites.size(), static_cast<size_t>(1));
+
+    const auto& families = suites[0]->familyVec();
+    BOOST_CHECK_EQUAL(families.size(), static_cast<size_t>(1));
+
+    const auto& tasks = families[0]->taskVec();
+    BOOST_CHECK_EQUAL(tasks.size(), static_cast<size_t>(1));
+
+    Task* task = tasks[0].get();
+    auto& mirrors = task->mirrors();
+    BOOST_CHECK_EQUAL(mirrors.size(), static_cast<size_t>(1));
+
+    // Verify the flag is initially clear
+    BOOST_CHECK(!task->get_flag().is_set(Flag::REMOTE_ERROR));
+
+    // Call mirror() which would normally set REMOTE_ERROR if the controller fails to start
+    // But with ECF_MIRROR_DISABLE set, it should return early and NOT set REMOTE_ERROR
+    mirrors[0].mirror();
+
+    // Verify the flag remains clear (proving mirror() did not attempt to start controller)
+    BOOST_CHECK(!task->get_flag().is_set(Flag::REMOTE_ERROR));
+}
+
 BOOST_AUTO_TEST_SUITE_END()
 
 BOOST_AUTO_TEST_SUITE_END()