diff --git a/dist/tools/backport_pr/backport_pr.py b/dist/tools/backport_pr/backport_pr.py
index 91ce72f91f..ce474766af 100755
--- a/dist/tools/backport_pr/backport_pr.py
+++ b/dist/tools/backport_pr/backport_pr.py
@@ -74,11 +74,17 @@ def _get_latest_release(branches):
     return (release_short, release_fullname)
 
 
-def _get_upstream(repo):
+def _find_remote(repo, user, repo_name):
     for remote in repo.remotes:
-        if (remote.url.endswith("{}/{}.git".format(ORG, REPO)) or
-                remote.url.endswith("{}/{}".format(ORG, REPO))):
+        if (remote.url.endswith("{}/{}.git".format(user, repo_name)) or
+                remote.url.endswith("{}/{}".format(user, repo_name))):
             return remote
+    raise ValueError("Could not find remote with URL ending in {}/{}.git"
+                     .format(user, repo_name))
+
+
+def _get_upstream(repo):
+    return _find_remote(repo, ORG, REPO)
 
 
 def _delete_worktree(repo, workdir):
@@ -168,22 +174,36 @@ def main():
     # Build topic branch in temp dir
     new_branch = args.backport_branch_fmt.format(release=release_shortname,
                                                  origbranch=orig_branch)
+    if new_branch in repo.branches:
+        print("ERROR: Branch {} already exists".format(new_branch))
+        sys.exit(1)
     worktree_dir = os.path.join(args.gitdir, WORKTREE_SUBDIR)
     repo.git.worktree("add", "-b",
                       new_branch,
                       WORKTREE_SUBDIR,
                       "{}/{}".format(upstream_remote, release_fullname))
-    bp_repo = git.Repo(worktree_dir)
-    # Apply commits
-    for commit in commits:
-        bp_repo.git.cherry_pick('-x', commit['sha'])
-    # Push to github
-    print("Pushing branch {} to origin".format(new_branch))
-    if not args.noop:
-        repo.git.push('origin', '{0}:{0}'.format(new_branch))
-    # Delete worktree
-    print("Pruning temporary workdir at {}".format(worktree_dir))
-    _delete_worktree(repo, worktree_dir)
+    try:
+        bp_repo = git.Repo(worktree_dir)
+        # Apply commits
+        for commit in commits:
+            bp_repo.git.cherry_pick('-x', commit['sha'])
+        # Push to github
+        origin = _find_remote(repo, username, REPO)
+        print("Pushing branch {} to {}".format(new_branch, origin))
+        if not args.noop:
+            repo.git.push(origin, '{0}:{0}'.format(new_branch))
+    except Exception as exc:
+        # Delete worktree
+        print("Pruning temporary workdir at {}".format(worktree_dir))
+        _delete_worktree(repo, worktree_dir)
+        # also delete branch created by worktree; this is only possible after
+        # the worktree was deleted
+        repo.delete_head(new_branch)
+        raise exc
+    else:
+        # Delete worktree
+        print("Pruning temporary workdir at {}".format(worktree_dir))
+        _delete_worktree(repo, worktree_dir)
 
     labels = _get_labels(pulldata)
     merger = pulldata['merged_by']['login']