This might seem rather a strange thing to ask, but is it allowed to buy a (paper) one day travelcard from Reading to all London zones and then start the journey in London? The reason for asking is that I'm meeting a friend in London, travelling around the city and then both travelling back to Reading; I will of course just use a travelcard in the usual way for myself, but for them the cost if the journey was done contactless (or a mixture of that and a single from London) would be much the same, plus both of us having travelcards would give the possibility of 2 for 1 entrance to London attractions. The Conditions of Carriage seem to suggest it's allowed but aren't explicit: 16.2 suggests it's OK to start at an intermediate station (which in this case would be somewhere within the London underground network), but condition 11.3 is a bit ambiguous as to whether it's OK to use just the return part of a return ticket if you haven't used (and won't use) the outward part. The fact that a travelcard is just a single ticket (as against two for a normal return) might also complicate things.