Yes, that is every hour of the week. I don't understand how this is legal? I must answer teams support requests at any time of day, as we have offices in America, Europe and Asia and I must be at a computer to provide any fixes required. That means I can't leave the house at any time aside from also completing my required 40 hours in the office, so I have to drive there and back for 30 minutes each day.
I started this job 4 months ago and asked in the interview whether on call time would be required, as it was a deal breaker, and they said 'no, no requirement for work outside of 40 hours a week in the office'.
I'm sick of this shit employers pull on you when they think you have no other choice. Does anybody have any UK based advice to this situation? Surely they cannot change my contracted hours without my consent.