Ahh, so the UK wishes to force Google to provide a backdoor. Presumably only for accounts that are UK residents. But what I visit the UK as a tourist? Can they demand access? Such complexities, and Google will presumably resist them.

Google does have a detailed legal process, which makes it pretty clear that Google sees itself operating as a U.S. institution, and external requests need to go through MLATs between other countries and ours. I'm guessing that the UK wants something far more direct than this.