The assessment seen by BuzzFeed News is being kept tightly guarded inside government. It was prepared by officials across Whitehall for the Department for Exiting the European Union (DExEU) and is reportedly being presented to key ministers in one-to-one meetings this week ahead of discussion at the Brexit cabinet subcommittee next week.Asked why the prime minister was not making the analysis public, a DExEU source told BuzzFeed News: "Because it's embarrassing."