I have another #ThinkingUtopia idea.
Buckingham Palace: let's kick out the royals and turn it into a part homeless hostel and soup kitchen, but also for small enterprises. Like, a kitchen garden & small forest garden plus chickens, supplying the soup kitchen.
Maybe a repair cafe & bike shop, which also teaches maintenance skills. Plus small scale solar & wind power projects suitable for urban areas. Homeless people can take part, learn how, or not, as they prefer.
Could also have beekeeping, run cooking, practical skill (i.e. sewing) & gardening classes, and rent some rooms out to community groups.