diff --git a/src/testdir/test_vim9_cmd.vim b/src/testdir/test_vim9_cmd.vim
index 7b2edfd..cfbac9a 100644
--- a/src/testdir/test_vim9_cmd.vim
+++ b/src/testdir/test_vim9_cmd.vim
@@ -1425,6 +1425,17 @@
   assert_equal([0, 1, 2], g:therange)
   unlet g:therange
 
+  # use exclamation mark for locking deeper
+  g:nestedlist = [1, [2, 3], 4]
+  lockvar! g:nestedlist
+  try
+    g:nestedlist[1][0] = 9
+  catch /E1119:/
+    caught = true
+  endtry
+  assert_true(caught)
+  unlet g:nestedlist
+
   var d = {a: 1, b: 2}
   d.a = 3
   d.b = 4
diff --git a/src/version.c b/src/version.c
index 576c06c..e77826c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4227,
+/**/
     4226,
 /**/
     4225,
diff --git a/src/vim9cmds.c b/src/vim9cmds.c
index 1af2a15..716a404 100644
--- a/src/vim9cmds.c
+++ b/src/vim9cmds.c
@@ -223,10 +223,12 @@
 	ret = FAIL;
     else
     {
-	vim_snprintf((char *)buf, len, "%s %d %s",
-		eap->cmdidx == CMD_lockvar ? "lockvar" : "unlockvar",
-		deep,
-		p);
+	char *cmd = eap->cmdidx == CMD_lockvar ? "lockvar" : "unlockvar";
+
+	if (deep < 0)
+	    vim_snprintf((char *)buf, len, "%s! %s", cmd, p);
+	else
+	    vim_snprintf((char *)buf, len, "%s %d %s", cmd, deep, p);
 	ret = generate_EXEC_copy(cctx, isn, buf);
 
 	vim_free(buf);