diff --git a/include/mapnik/value_hash.hpp b/include/mapnik/value_hash.hpp
index f1119e0b3..3a2536c36 100644
--- a/include/mapnik/value_hash.hpp
+++ b/include/mapnik/value_hash.hpp
@@ -37,11 +37,6 @@
 
 namespace mapnik { namespace detail {
 
-inline void hash_combine(std::size_t & seed, std::size_t val)
-{
-    seed ^= val + 0x9e3779b9 + (seed << 6) + (seed >> 2);
-}
-
 struct value_hasher
 {
     std::size_t operator() (value_null val) const