Just to add to all the confusion.........by the way thank you for all the informative replies.
I've just checked out my company B737NG ops man. It states that for departure in the UK, only 1 min seperation will be provided and my company has accepted this policy. The commander should state if he/she requires more. So I've basically just shown myself up
as I didnt have a clue that this was there.
The issue really only arose as we had been cleared to line up after the departing B757. My switched on colleague pointed out that there was traffic on approach. We stopped well short of the active RW and clarified that we needed 2 mins spacing. Had we asked after line up a G/A would have probably have been required. I really thought that 2 mins was the minimum provided. The controller asked us in future to inform ATC earlier.
You learn something new every day in this game.
Thanks to you all!!
PMR