Not to say it won't air on a Saturday, but with Atlantis the BBC were upfront that this was Saturday evening show. They're being cagier with this.
Well the offical Blurb talks about it in much the same terms that Robin Hood/Merlin/DW got talked about.
"The series bursts with escapism, adventure and romance and is set to thrill audiences with cracking stories of the week."
Not very post-watershed sounding.