If we woke up tomorrow and...
jodrellblank: All technology? I guess we're back at the bottom of the Civilization advances tree, eh? Do you want triremes, maths, militia or granaries?England has ~65 millions of people. Take away all manmade technology (including buildings, tarmac, concrete) and any city would be many square miles of bare earth collapsing into holes where sewers and tunnels and underground trains once were.Within a day or two it would be many square miles of human waste, corpses, mud if it rained, and people making their way to the nearest rivers.Within a couple of weeks, significant fractions of people have starved or died of lack of medical treatment, fighting, illness from river water contaminated with sewage and corpses, etc.OK, you can drink from the river you may not get ill for a while. What can you eat but other people? City areas -> wastelands.Out in the country, farmers with easily harvested crops in season are the best off, until they get looted. With no food stores or shops, animals and current crops will be eaten quickly and that's pretty much that. Good luck surviving on hedgerow food and hunting with no experience and everyone else trying to as well.Some strong willed resourceful people in remote niches will survive (nobody could travel to them very quickly). After a few years we'll see who. Small farms, maybe some farm animals, fast growing trees coming into usable sizes. Levers, (wooden) wheels, barrows, hammers hoes, heaters, cookers, flint/stone axes, they'll be around.Maybe in short order some beach sand melting -> glass jars, glasses. The people who survive are the people who currently live with reduced technology and will be busy staying alive.What then? I don't know. A few decades to a population big enough and connected enough for mass trade, I suppose. By then a similar sort of grind up through metalwork, blacksmithing, banking, debt, economic collapse...What technology could we skip to that would hasten us through such developments? I say at least two hundred years.