"It's the only time nobody needs anything from me"

This is the objection that deserves the most respect, because it's the one that isn't really about sleep.

For a lot of people the lie-in isn't nine hours of unconsciousness. It's seven hours of sleep and two hours of lying there. Half awake, warm, unbothered, no list. Perhaps the phone, perhaps a book, perhaps nothing. If you've got children it may be the only two hours in the week when they're occupied elsewhere and you're not on duty. If you live alone it may be the only stretch when you're not performing for anyone. That's a real need, and telling you to get up and go for a brisk walk at seven is the kind of advice that gets a book thrown across a room.

So don't lose the hour. Move it. What the hour needs is that nobody wants anything from you, and that you're not required to be anywhere. It doesn't need to be at nine, and it doesn't need to be horizontal. It can be seven, with the curtains open and a mug, in the same bed or a chair by a window, with the same book and the same nothing. What your clock needs is light and an upright body at something close to the weekday time. What you need is unclaimed time. Those two things aren't in conflict. The conflict was only ever between unclaimed time and darkness, and the darkness was never the point.

If the house is the problem, if getting up means being found and asked for things, then the hour is a negotiation, not a sleep question, and it's worth having out loud. Saturday from seven to eight is mine, and I'll be in the kitchen or the garden and I'm not to be asked for anything unless there's blood. Most households can grant that, and the ones that can't have a different problem that this book can't solve.

There's one more thing the lie-in gives that's worth naming, and that's the absence of the alarm, the waking naturally. That's a pleasure and you can keep it. Chapter 17 is about a wake time held within a window, and inside that window you can wake as your body wakes, without a noise. What you give up is the extra two hours beyond the window, and I'd guess that when you look closely, those two hours were mostly the lying there, which you can have with the light on.