Speaking as a Civilian ATCO, ready for departure is the correct r/t. CAP413 refers, and can be found here
http://www.caa.co.uk/docs/33/CAP413.PDF
In the civil world we usually expect you to be ready for climb at a similar time to being ready for departure, you tend to get a lot of grass stains otherwise!
Don't know how the Military do it. (and don't want to either!!)