15-06-2018 03:51 PM - last edited: 15-06-2018 03:52 PM
Might not be available at all for that particular event. This page does note:
"You can usually book passes from the day the arena tickets go on general sale. Sometimes there’s a delay in releasing passes so check ‘Sky VIP’ in your My Sky app later. If you still can’t book passes after two weeks, Sky Backstage probably isn’t open for the show you’re seeing. The O2 has the right to close Sky Backstage but this doesn't happen very often."