diff --git a/include/boost/numeric/ublas/config.hpp b/include/boost/numeric/ublas/config.hpp
index ab2dff8d..a420e5f0 100644
--- a/include/boost/numeric/ublas/config.hpp
+++ b/include/boost/numeric/ublas/config.hpp
@@ -72,6 +72,7 @@
 #define BOOST_UBLAS_NO_CMATH
 #endif
 
+// We must disable element proxies as they require template partial specialisation
 #define BOOST_UBLAS_NO_ELEMENT_PROXIES
 
 // This seems to be a problem in boost.config, but won't be fixed.