"I haven't a clue, honestly. I remember, when I'd first found Milliways, and this was some time before I knew you were even there, I hated it. Having no one I could talk to. I think..."

He frowns, thoughtfully.

"I think in some ways Milliways has prompted me to be more honest about the things I can talk about. I suppose that, er, explains the letter I left for you."