diff --git a/CMakeLists.txt b/CMakeLists.txt
index f62398be..b4a847ae 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -69,6 +69,9 @@ include_directories( ${IODA_INCLUDE_DIRS} )
 find_package( oops REQUIRED )
 include_directories( ${OOPS_INCLUDE_DIRS} )
 
+find_package(SHUM REQUIRED)
+include_directories( ${SHUM_INCLUDE_DIR} )
+
 ################################################################################
 # Export package info
 ################################################################################
diff --git a/deps/CMakeLists.txt b/deps/CMakeLists.txt
index eb126b31..b6b63393 100644
--- a/deps/CMakeLists.txt
+++ b/deps/CMakeLists.txt
@@ -42,6 +42,15 @@ ${CMAKE_Fortran_FLAGS}"
 -check format \
 -check pointers \ 
 -check uninit \
+${CMAKE_Fortran_DEBUG_FLAGS}"
+  )
+elseif ("${CMAKE_Fortran_COMPILER_ID}" MATCHES "NAG")
+  set(OPS_DEFAULT_Fortran_FLAGS "\
+-double \
+${CMAKE_Fortran_FLAGS}"
+#-Wp,-P \
+  )
+  set(CMAKE_Fortran_DEBUG_FLAGS "\
 ${CMAKE_Fortran_DEBUG_FLAGS}"
   )
 endif()
diff --git a/deps/gcom/CMakeLists.txt b/deps/gcom/CMakeLists.txt
index 7a1fc2fd..56a67b35 100644
--- a/deps/gcom/CMakeLists.txt
+++ b/deps/gcom/CMakeLists.txt
@@ -13,8 +13,7 @@ endif()
 
 set(CMAKE_Fortran_FLAGS "\
 ${OPS_DEFAULT_Fortran_FLAGS} \
-${GCOM_EXTRA_Fortran_FLAGS} \
-${CMAKE_Fortran_FLAGS}")
+${GCOM_EXTRA_Fortran_FLAGS}")
 
 set(GCOM_SOURCE_FILES
   gc/gc__abort.c
@@ -213,9 +212,16 @@ set(GCOM_SOURCE_DIRS
 
 # Setup the parallel version of the gcom library
 
-ecbuild_add_library(
-  TARGET gcom
-  SOURCES ${GCOM_SOURCE_FILES})
+if("${CMAKE_Fortran_COMPILER_ID}" MATCHES "NAG")
+  ecbuild_add_library(
+    TARGET gcom
+    SOURCES ${GCOM_SOURCE_FILES}
+    LINKER_LANGUAGE CXX)
+else()
+  ecbuild_add_library(
+    TARGET gcom
+    SOURCES ${GCOM_SOURCE_FILES})
+endif()
  
 target_compile_definitions(gcom PRIVATE 
   GC_VERSION="'7.2'" 
@@ -240,9 +246,16 @@ target_include_directories(gcom
 
 # Setup the serial version of the gcom library
 
-ecbuild_add_library(
-  TARGET gcom_serial
-  SOURCES ${GCOM_SOURCE_FILES})
+if("${CMAKE_Fortran_COMPILER_ID}" MATCHES "NAG")
+  ecbuild_add_library(
+    TARGET gcom_serial
+    SOURCES ${GCOM_SOURCE_FILES}
+    LINKER_LANGUAGE CXX)
+else()
+  ecbuild_add_library(
+    TARGET gcom_serial
+    SOURCES ${GCOM_SOURCE_FILES})
+endif()
 
 # For the serial version, skip the MPI_SRC symbol...
 target_compile_definitions(gcom_serial PRIVATE
diff --git a/deps/odb/CMakeLists.txt b/deps/odb/CMakeLists.txt
index 5dc41af9..779b3230 100644
--- a/deps/odb/CMakeLists.txt
+++ b/deps/odb/CMakeLists.txt
@@ -9,17 +9,23 @@ endif()
 
 set(CMAKE_Fortran_FLAGS "\
 ${OPS_DEFAULT_Fortran_FLAGS} \
-${ODB_EXTRA_Fortran_FLAGS} \
-${CMAKE_Fortran_FLAGS}")
+${ODB_EXTRA_Fortran_FLAGS}")
 
 set(ODB_SOURCE_FILES
   stubs/parkind1.F90
   stubs/yomhook.F90
 )
 
-ecbuild_add_library(
-  TARGET odb
-  SOURCES ${ODB_SOURCE_FILES})
+if("${CMAKE_Fortran_COMPILER_ID}" MATCHES "NAG")
+  ecbuild_add_library(
+    TARGET odb
+    SOURCES ${ODB_SOURCE_FILES}
+    LINKER_LANGUAGE CXX)
+else()
+  ecbuild_add_library(
+    TARGET odb
+    SOURCES ${ODB_SOURCE_FILES})
+endif()
 
 get_target_property(ODB_Fortran_MODULE_DIRECTORY odb Fortran_MODULE_DIRECTORY)
 
diff --git a/deps/ops/CMakeLists.txt b/deps/ops/CMakeLists.txt
index 1445b93b..71096a9c 100644
--- a/deps/ops/CMakeLists.txt
+++ b/deps/ops/CMakeLists.txt
@@ -13,8 +13,7 @@ endif()
 
 set(CMAKE_Fortran_FLAGS "\
 ${OPS_DEFAULT_Fortran_FLAGS} \
-${OPS_EXTRA_Fortran_FLAGS} \
-${CMAKE_Fortran_FLAGS}")
+${OPS_EXTRA_Fortran_FLAGS}")
 
 set(OPS_SOURCE_FILES
   code/GenMod_ModelIO/GenMod_ModelIO.F90
@@ -111,6 +110,7 @@ foreach (file ${OPS_SOURCE_FILES})
   list(APPEND OPS_SOURCE_DIRS "${dir}")
 endforeach()
 list(REMOVE_DUPLICATES OPS_SOURCE_DIRS)
+include_directories( ${OPS_SOURCE_DIRS} )
 
 # Find extra dependencies
 
@@ -119,8 +119,14 @@ find_package(SHUM REQUIRED)
 
 # Setup the parallel version of the ops library
 
-ecbuild_add_library(TARGET ops
-  SOURCES ${OPS_SOURCE_FILES})
+if("${CMAKE_Fortran_COMPILER_ID}" MATCHES "NAG")
+  ecbuild_add_library(TARGET ops
+    SOURCES ${OPS_SOURCE_FILES}
+    LINKER_LANGUAGE CXX)
+else()
+  ecbuild_add_library(TARGET ops
+    SOURCES ${OPS_SOURCE_FILES})
+endif()
 
 target_compile_definitions(ops PRIVATE 
   EXTERNAL_GCOM
@@ -163,8 +169,14 @@ target_include_directories(ops
 
 # Setup the serial version of the ops library, linked to gcom_serial
 
-ecbuild_add_library(TARGET ops_serial
-  SOURCES ${OPS_SOURCE_FILES})
+if("${CMAKE_Fortran_COMPILER_ID}" MATCHES "NAG")
+  ecbuild_add_library(TARGET ops_serial
+    SOURCES ${OPS_SOURCE_FILES}
+    LINKER_LANGUAGE CXX)
+else()
+  ecbuild_add_library(TARGET ops_serial
+    SOURCES ${OPS_SOURCE_FILES})
+endif()
 
 target_compile_definitions(ops_serial PRIVATE
   EXTERNAL_GCOM
@@ -212,16 +224,32 @@ target_include_directories(ops_serial
 
 set(CMAKE_EXECUTABLE_SUFFIX .exe)
 
-ecbuild_add_executable(TARGET OpsProg_PrintCXFile
-  SOURCES
-  code/OpsProg_Utils/OpsMod_PrintCX.f90
-  code/OpsProg_Utils/OpsProg_PrintCXFile.F90)
+if("${CMAKE_Fortran_COMPILER_ID}" MATCHES "NAG")
+  ecbuild_add_executable(TARGET OpsProg_PrintCXFile
+    SOURCES
+    code/OpsProg_Utils/OpsMod_PrintCX.f90
+    code/OpsProg_Utils/OpsProg_PrintCXFile.F90
+    LINKER_LANGUAGE CXX)
+else()
+  ecbuild_add_executable(TARGET OpsProg_PrintCXFile
+    SOURCES
+    code/OpsProg_Utils/OpsMod_PrintCX.f90
+    code/OpsProg_Utils/OpsProg_PrintCXFile.F90)
+endif()
 target_link_libraries(OpsProg_PrintCXFile
   PRIVATE ops_serial)
 
-ecbuild_add_executable(TARGET OpsProg_PrintVarobs
-  SOURCES
-  code/OpsProg_Utils/OpsMod_PrintVarobs.f90
-  code/OpsProg_Utils/OpsProg_PrintVarobs.F90)
+if("${CMAKE_Fortran_COMPILER_ID}" MATCHES "NAG")
+  ecbuild_add_executable(TARGET OpsProg_PrintVarobs
+    SOURCES
+    code/OpsProg_Utils/OpsMod_PrintVarobs.f90
+    code/OpsProg_Utils/OpsProg_PrintVarobs.F90
+    LINKER_LANGUAGE CXX)
+else()
+  ecbuild_add_executable(TARGET OpsProg_PrintVarobs
+    SOURCES
+    code/OpsProg_Utils/OpsMod_PrintVarobs.f90
+    code/OpsProg_Utils/OpsProg_PrintVarobs.F90)
+endif()
 target_link_libraries(OpsProg_PrintVarobs
   PRIVATE ops_serial)
diff --git a/src/opsinputs/CMakeLists.txt b/src/opsinputs/CMakeLists.txt
index 88570491..7f14733e 100644
--- a/src/opsinputs/CMakeLists.txt
+++ b/src/opsinputs/CMakeLists.txt
@@ -43,6 +43,8 @@ if("${CMAKE_Fortran_COMPILER_ID}" MATCHES "GNU")
   set(FORTRAN_FLAGS_64_BIT_TYPES "-fdefault-real-8 -fdefault-integer-8")
 elseif ("${CMAKE_Fortran_COMPILER_ID}" MATCHES "Intel")
   set(FORTRAN_FLAGS_64_BIT_TYPES "-integer-size 64 -real-size 64")
+elseif ("${CMAKE_Fortran_COMPILER_ID}" MATCHES "NAG")
+  set(FORTRAN_FLAGS_64_BIT_TYPES "-double")
 endif()
 set_source_files_properties(opsinputs_cxgenerate_mod.F90 PROPERTIES
                             COMPILE_FLAGS "${FORTRAN_FLAGS_64_BIT_TYPES}")