diff --git a/src/util/arith_tools.cpp b/src/util/arith_tools.cpp
index df997b48a51..1f05e2ed42a 100644
--- a/src/util/arith_tools.cpp
+++ b/src/util/arith_tools.cpp
@@ -96,23 +96,6 @@ bool to_integer(const constant_exprt &expr, mp_integer &int_value)
   return true;
 }
 
-/// convert a positive integer expression to an unsigned int
-/// \par parameters: a constant expression and a reference to an unsigned int
-/// \return an error flag
-bool to_unsigned_integer(const constant_exprt &expr, unsigned &uint_value)
-{
-  mp_integer i;
-  if(to_integer(expr, i))
-    return true;
-  if(i<0)
-    return true;
-  else
-  {
-    uint_value = numeric_cast_v<unsigned>(i);
-    return false;
-  }
-}
-
 constant_exprt from_integer(
   const mp_integer &int_value,
   const typet &type)
diff --git a/src/util/arith_tools.h b/src/util/arith_tools.h
index 395ab9b5f62..4f67c810b92 100644
--- a/src/util/arith_tools.h
+++ b/src/util/arith_tools.h
@@ -10,7 +10,6 @@ Author: Daniel Kroening, kroening@kroening.com
 #ifndef CPROVER_UTIL_ARITH_TOOLS_H
 #define CPROVER_UTIL_ARITH_TOOLS_H
 
-#include "deprecate.h"
 #include "invariant.h"
 #include "mp_arith.h"
 #include "optional.h"
@@ -26,10 +25,6 @@ class typet;
 /// \return False if, and only if, the conversion was successful.
 bool to_integer(const constant_exprt &expr, mp_integer &int_value);
 
-// returns 'true' on error
-DEPRECATED(SINCE(2018, 9, 29, "Use numeric_cast<unsigned>(e) instead"))
-bool to_unsigned_integer(const constant_exprt &expr, unsigned &uint_value);
-
 /// Numerical cast provides a unified way of converting from one numerical type
 /// to another.
 /// Generic case doesn't exist, this has to be specialized for different types.