It doesn't escape the economy. This is the kind of bizarre left-wing isolationism/nationalism that seems to be rife amongst people who don't understand free markets.

If you pay money to Palantir, they are providing a service in return. That service is investment in your own economy, you pay them and then you own the thing they produce. Money does not "escape", the same amount of money is there before and after. The reason the UK is doing bad is this kind of bizarre economic xenophobia combined with a complete hostility to any kind of innovation or change. The question is: why don't we have a company competing with Palantir? Should be very obvious.