diff -r c793d62cdecc Lib/test/test_import.py
--- a/Lib/test/test_import.py	Sun Aug 19 17:57:29 2012 -0400
+++ b/Lib/test/test_import.py	Mon Aug 20 16:39:35 2012 +1000
@@ -10,9 +10,8 @@
 import textwrap
 import shutil
 
-from test.test_support import (unlink, TESTFN, unload, run_unittest, rmtree,
-                               is_jython, check_warnings, EnvironmentVarGuard)
-from test import symlink_support
+from test.test_support import (unlink, TESTFN, unload, run_unittest, rmtree, is_jython, check_warnings, EnvironmentVarGuard)
+import symlink_support
 from test import script_helper
 
 def remove_files(name):
@@ -119,7 +118,7 @@
             remove_files(TESTFN)
             unload(TESTFN)
             del sys.path[0]
-
+            
     def test_imp_module(self):
         # Verify that the imp module can correctly load and find .py files
 
@@ -305,7 +304,73 @@
             del sys.path[0]
             remove_files(TESTFN)
 
+class FilePermissionTests(unittest.TestCase):
+    def setUp(self):
+        self.filename = 'readonlyPermission' 
+        self.pyfilename = self.filename + os.extsep + 'py'
+        self.pycfilename = self.filename + os.extsep + 'pyc'
+        self.pyofilename = self.filename + os.extsep + 'pyo'
 
+    def tearDown(self):
+        self.clean_up_file(self.pyfilename)
+        self.clean_up_file(self.pycfilename)
+        self.clean_up_file(self.pyofilename)
+        
+    def clean_up_file(self,filename):
+        if os.path.exists(filename):
+            os.chmod(filename, (stat.S_IWUSR | stat.S_IRUSR))
+            os.remove(filename)
+    def check_py_file_permission(self, permission):
+        # Check that the created .pyc and .pyo have exactly the same
+        # read/write permission as the .py file
+        print '-' * 50
+        print 'test_imp_file_permission'
+        
+        self.create_file_and_check( permission )
+        
+        self.clean_up_file(self.pyfilename)
+        
+        self.create_file_and_check( permission )
+    
+    def create_file_and_check(self,permission):
+        p = permission 
+        f = open(self.pyfilename, 'w').close()
+        # os.chmod(self.pyfilename, (stat.S_IRUSR | stat.S_IRGRP | stat.S_IROTH))
+        os.chmod(self.pyfilename, p)
+        s_py = os.stat(self.pyfilename)
+        print s_py
+        print 'stat.S_IMODE(s_py.st_mode): o%o' % stat.S_IMODE(s_py.st_mode)
+        
+        # assert .py file has read-only permission
+        # 0444 on windows and 0400 on other systems
+        if os.name == 'nt':
+            self.assertEqual( stat.S_IMODE(s_py.st_mode), 
+                              p | p >> 3 | p >> 6 )
+        else:
+            self.assertEqual( stat.S_IMODE(s_py.st_mode), 
+                              p )
+            
+        import imp
+        imp.load_module(self.filename, *imp.find_module(self.filename))
+        # __import__( filename )
+        s_pyc = os.stat(self.pycfilename)
+        print 'stat.S_IMODE(s_pyc.st_mode): o%o' % stat.S_IMODE(s_pyc.st_mode)
+        
+        # assert .pyc file also has read-only permission
+        # 0444 on windows and 0400 on other systems
+        if os.name == 'nt':
+            self.assertEqual( stat.S_IMODE(s_py.st_mode), 
+                              p | p >> 3 | p >> 6 )
+        else:
+            self.assertEqual( stat.S_IMODE(s_py.st_mode),
+                              p )
+        
+    def test_readonly_permission(self):
+        self.check_py_file_permission( permission=stat.S_IRUSR )
+    
+    def test_write_permission(self):
+        self.check_py_file_permission( permission=(stat.S_IWUSR | stat.S_IRUSR) )
+            
 class PycRewritingTests(unittest.TestCase):
     # Test that the `co_filename` attribute on code objects always points
     # to the right file, even when various things happen (e.g. both the .py
@@ -548,8 +613,10 @@
         sys.path[:] = self.orig_sys_path
 
 def test_main(verbose=None):
-    run_unittest(ImportTests, PycRewritingTests, PathsTests,
-        RelativeImportTests, TestSymbolicallyLinkedPackage)
+    # run_unittest(ImportTests, PycRewritingTests, PathsTests,
+        # RelativeImportTests, TestSymbolicallyLinkedPackage,
+        # FilePermissionTests)
+    run_unittest(FilePermissionTests)
 
 if __name__ == '__main__':
     # Test needs to be a package, so we can do relative imports.
diff -r c793d62cdecc Python/import.c
--- a/Python/import.c	Sun Aug 19 17:57:29 2012 -0400
+++ b/Python/import.c	Mon Aug 20 16:39:35 2012 +1000
@@ -875,8 +875,24 @@
        which is just fine (since it's only a cache).
        XXX If the file exists and is writable but the directory is not
        writable, the file will never be written.  Oh well.
+	   If the os is Windows then unlink() will fail on read-only files,
+	   so chmod() is used to ensure the file has write access setting
+	   before unlink is called.
     */
     int fd;
+#if defined(MS_WINDOWS)
+	int cd;
+	cd = chmod(filename, _S_IWRITE | _S_IREAD);
+	if ( cd < 0 )
+	{
+		if ( errno != ENOENT )
+		{
+			printf("Problem modifying permission on .pyc or .pyo file\n");
+			printf("This means thie file might not have been deleted\n");
+		}
+		// otherwise the file doesn't exist so it's okay
+	}
+#endif
     (void) unlink(filename);
     fd = open(filename, O_EXCL|O_CREAT|O_WRONLY|O_TRUNC
 #ifdef O_BINARY
@@ -886,7 +902,7 @@
             , mode, "ctxt=bin", "shr=nil"
 #else
             , mode
-#endif
+#endif	
           );
     if (fd < 0)
         return NULL;