* the UK may not want critical infrastructure provided elsewhere
* the UK may have research/student folk who would have previously worked on Galileo, but now cannot
* the UK may want to fund this as a vehicle for space research in general
* UK wants a big vanity project to show how much better they are out of the EU
What makes you think that is most plausible?
* the UK may not want critical infrastructure provided elsewhere
* the UK may have research/student folk who would have previously worked on Galileo, but now cannot
* the UK may want to fund this as a vehicle for space research in general