You are comparing states with groceries...let's compare the Afganistan war with an afterschool fight or terrorists with pranksters and see where it leads us.

Spying activities are hostile actions. They are used to gain unfair economic advantage, overtrow governments, win elections(for their fav candidate) and other nasty stuff.

If the british government needs more data to find terrorists they could use their political power to improve the data sharing at the EU level.