diff --git a/src/util/demangle.cpp b/src/util/demangle.cpp
index 01ea83ec..e8b0754e 100644
--- a/src/util/demangle.cpp
+++ b/src/util/demangle.cpp
@@ -61,13 +61,13 @@ namespace util {
         sym_initialised = true;
     }
 
-    std::string demangle(const char* symbol) {
+    std::string demangle(const char* symbol) noexcept {
         // If the symbol is null or the empty string then just return it
         if (symbol == nullptr || symbol[0] == '\0') {
             return "";
         }
 
-        std::lock_guard<std::mutex> lock(symbol_mutex);
+        const std::lock_guard<std::mutex> lock(symbol_mutex);
 
         // Initialise the symbols if we have to
         if (!sym_initialised) {
@@ -110,7 +110,7 @@ namespace util {
      *
      * @return the demangled symbol, or the original string if it could not be demangled
      */
-    std::string demangle(const char* symbol) {
+    std::string demangle(const char* symbol) noexcept {
 
         if (symbol == nullptr) {
             return {};
diff --git a/src/util/demangle.hpp b/src/util/demangle.hpp
index e92a6035..cb18b82a 100644
--- a/src/util/demangle.hpp
+++ b/src/util/demangle.hpp
@@ -28,7 +28,7 @@
 namespace NUClear {
 namespace util {
 
-    std::string demangle(const char* symbol);
+    std::string demangle(const char* symbol) noexcept;
 
 }  // namespace util
 }  // namespace NUClear