We twist onto Corsica's most dramatic mountain pass. The Mediterranean plunges below, and lichen-bearded pines part on rocks that thrust upwards like giants' teeth. Four-year-old Tallulah sighs. "I wish I was in Stockwell."

Tallulah's seen a thousand passes. Truth is, she's lonely. After a year on the road, I hoped she'd stop missing her friends, but she longs for them more than ever. What she needs, she says wistfully, is "someone to be naughty with".

Richard and I have each other to be naughty with - though we're usually too exhausted for anything too spectacular. After driving a hundred miles, exploring a city, interviewing a professor of linguistics, playing with playdough, foraging for fungi and cooking supper, we long only to collapse into bed. But we can't: we have to make our bed before lying on it. Making our bed does not mean flicking the duvet, but actually constructing the damn thing.

We contemplate staying put. Should we park up and buy that ruined farmhouse - huge and cheap, so cheap? Should we flee the "delights" of Stockwell? We also miss our friends, but Stockwell's burglars and incontinent dogs do not exactly summon us, siren-like, across the waves.

I ponder these questions during our visit to Dorothy Carrington. I first encountered this English writer - acknowledged even by the jealous French as the best writer on Corsica - in a Corsican tourist brochure. It quoted her last wish as to be buried on the south coast, facing the sea, so I was surprised to find her still alive. She arrived in 1948, intending to write a travel book, and was so captivated that she stayed.

We find her in a poky basement off the main thoroughfare in Ajaccio, Corsica's capital. Tallulah is looking forward to meeting her. She envisages someone like Granny, reading her stories and feeding her cake. But as soon as we arrive I know it is all wrong. The children are not to run about, there are precious things within reach, they can use her pencils only if they don't chew them. Echoing floor tiles inspire Xanthe to utter piercing shrieks. Dorothy flings herself back in her chair, casting up her hands. "No no, I simply can't, I can't go on with this. I simply can't." Richard flees with the children to a bar.

Privately, she criticises the violence of Corsican separatists, but being a foreigner feels unqualified to condemn it. As for her books, she has great reviews but few sales. So, there she is: an outsider, widowed, childless and penniless, too frail now for her annual journey home. Is this what comes of staying on? There's not much between exit and exile.

So, it is fortunate, perhaps, that we have become addicted to perpetual motion. Embodying the EU's trite slogan "Europe on the Move", we take a ferry to Sardinia. Before embarking we call Dorothy. "Goodbye," she says. "Send my love to your terrible children."