A one-day data sprint on London housing, organised by Jam Coombes at Newspeak House. The premise is that the planning and housing data needed to understand the crisis already exists, and the work is turning it into an argument someone can act on.

Teams of data scientists, urban planners and policy people take real London planning and housing datasets and build the most well-evidenced story they can — policy briefs, dashboards or models, not toy problems. Runs 10:00 to 19:30 on the First Floor, with cash prizes voted on by the other hackers.

Why go: a hackathon with a real dataset and a real question beats a sponsored one with neither, and the judging-by-peers format keeps it honest. Best for data scientists, analysts and planners who want a day on something that matters.