I agree with the earlier post re no photo ID required on internals (also BD). I domestic commute weekly and have not shown a photo ID anywhere since the August LHR scare (- when I was returning from Middle East and staying in LHR hotel overnight...woke up to mayhem - but another story
.)
Have not been asked for anything since then. with BD online check-in and printing boarding card that has done it. I still feel wary though, and always keep my driving licence (with euro style photo ID) in my hand luggage.