Rudi will know but that construction (rails bolted to cantle) does not jibe with Brooks for me. By the nose shape I would guess something Italian or French...maybe, and with no maker's ID and steel rivets, etc. likely a budget model.
EDIT: after looking at every saddle on Velobase I don't see a one that matches this one from England, Italy, France or Japan. The chrome rails that BOLT to cantle plate seems more present as Japanese construction, almost zero Brooks or Ideales use this, then combine the steel rivets and side flap hole pattern...nothing matches.
This is a riddle for @
rhm if ever there was one.