Originally Posted by corporate-wage-slave

I think I would divide my answer to this into two parts - what the Regulation says, and what BA will actually do. For the Regulations the 3 options apply for delays as well as cancellations, the required delay period being 5 hours, which would be the case here given it's the last flight of the night. So I think you are covered in this circumstance. If hypothetically there was a night flight which kept the delay below 5 hours then BA could insist you take it, which is understandable since it minimises their risk to pay Article 7 compensation. In terms of what BA will actually do, there would be no problem here. They will rebook you according to anything sensible for which there is availability (at the airport) or for a slightly stricter set of rules if using the Contact Centre but it won't get in the way of your plans here either way. You would only get 1 night hotel accommodation if - as one would expect - there was Saturday availability for LHR-EDI.