Barring any last minute delays, Torchwood: Children of Earth launches here in the UK on BBC One on June 15 and runs through that week, ending June 19th.
For a while I've been saying that there's no way the series can begin until the second series of Ashes to Ashes (which started last Monday) has concluded its run. That series is scheduled to end June 8th - and with comments by John Barrowman on the Jonathan Ross Radio 2 show recently - presented by David Tennant and Catherine Tate - that Torchwood airs sometime in June, that leaves either a June 15th, June 22nd or June 29th launch.
Add into the mix that the current issue of Torchwood Magazine, out today, is full of previews for Children of Earth and that its next issue is out June 25th, with a very spoilery interview with Russell T Davies and set reports from the series, including a look at the mysterious 456, one can deduce that the series is expected to have concluded its run by then.
The only way that'd be possible is a June 15th launch - because obviously June 29th is after that new issue is out (so would completely ruin the series a whole week before transmission) and even June 22nd is a bit of a danger area, as subscribers receive copies of their magazines early. June 15th-19th would be fine, and have concluded by the time the magazine is out.
(The case could be made that the series launch could occur June 22nd, and the contents of that new issue only cover the first half of the series - at this point I've chosen the June 15th launch date because it's the most likely. It's 80/20 in its favour)
Also, you have the June 22nd launch of the Blu Ray, to tie in with hype that the series will have gathered by that point, to maximise sales.
People are under the assumption that the schedules are made up on a whim a couple of weeks before transmission. If you know anything about scheduling, you'll know that's simply not true. It's a very complex affair, and programmes are sometimes slotted into schedule a whole year before transmission - look at Doctor Who, with its traditional Christmas Special, and then following Easter series launch. Of course, though it's that complex, changes are still being made here and there, until the day that listings magazines are given the schedules to print (at which point changes are rarely made).
No doubt some readers will attack me online and in the comments section below for making such a guess with regards to series lauch. So what. Go ahead. Do your worst. I'm merely communicating with you what is now a very educated guess, based upon several truths and realities that we know to be fact.
Pencil in June 15th (and June 22nd to be on the safe side - but it's definitely one of those two dates)!