UK Cable/Satellite network Watch has indicated plans to air a week of Series 1 of Torchwood - 15 to 19 June at 10PM UK Time.
The listing suggests that Watch's repeats will air straight after the new Torchwood: Children Of Earth episodes air on BBC One. This suggests that the BBC One premieres for Torchwood: Children Of Earth would be at 9PM UK Time on 15 to 19 June.
From the June Monthly Highlights:
Weeknights, 10pm (from Monday 15th June)
With brand-new Torchwood on BBC One, Watch continues the Torchwood flavour with stripped episodes every week night. ...
In the first episode, a brutal murder leads WPC Gwen Cooper to Torchwood, a journey that will change their lives forever. With four more episodes from series one across the week, fans can enjoy brand-new Torchwood on BBC One, as well as classic Torchwood on Watch straight afterwards.
The BBC will not announce an airdate and time for Torchwood on BBC One until closer to broadcast to allow themselves to change plans as needed. BBC One's scheduling needs will be the deciding factor in when the new Torchwood episodes air.