diff --git a/devel.but b/devel.but
index 9668651..02f9cfa 100644
--- a/devel.but
+++ b/devel.but
@@ -3091,6 +3091,17 @@ Returns a descriptive game ID (i.e. one in the form
 \cq{params:description}) describing the game currently active in the
 mid-end. The returned string is dynamically allocated.
 
+\H{midend-get-random-seed} \cw{midend_get_random_seed()}
+
+\c char *midend_get_random_seed(midend *me)
+
+Returns a random game ID (i.e. one in the form \cq{params#seedstring})
+describing the game currently active in the mid-end, if there is one.
+If the game was created by entering a description, no random seed will
+currently exist and this function will return \cw{NULL}.
+
+The returned string, if it is non-\cw{NULL}, is dynamically allocated.
+
 \H{midend-can-format-as-text-now} \cw{midend_can_format_as_text_now()}
 
 \c int midend_can_format_as_text_now(midend *me);
diff --git a/midend.c b/midend.c
index 53dca21..fddf01d 100644
--- a/midend.c
+++ b/midend.c
@@ -1304,6 +1304,21 @@ char *midend_get_game_id(midend *me)
     return ret;
 }
 
+char *midend_get_random_seed(midend *me)
+{
+    char *parstr, *ret;
+
+    if (!me->seedstr)
+        return NULL;
+
+    parstr = me->ourgame->encode_params(me->curparams, TRUE);
+    assert(parstr);
+    ret = snewn(strlen(parstr) + strlen(me->seedstr) + 2, char);
+    sprintf(ret, "%s#%s", parstr, me->seedstr);
+    sfree(parstr);
+    return ret;
+}
+
 char *midend_set_config(midend *me, int which, config_item *cfg)
 {
     char *error;
diff --git a/puzzles.h b/puzzles.h
index e8a75c2..fbd1828 100644
--- a/puzzles.h
+++ b/puzzles.h
@@ -251,6 +251,7 @@ config_item *midend_get_config(midend *me, int which, char **wintitle);
 char *midend_set_config(midend *me, int which, config_item *cfg);
 char *midend_game_id(midend *me, char *id);
 char *midend_get_game_id(midend *me);
+char *midend_get_random_seed(midend *me);
 int midend_can_format_as_text_now(midend *me);
 char *midend_text_format(midend *me);
 char *midend_solve(midend *me);