Television and movie producers currently have a good deal in Great Britain, not in small part due to stability in various markets and some funding. For example, Game of Thrones, an HBO production, is filmed in Norther Ireland with funding from the European Regional Development fund.
Both the stability and some of the funding for various productions is now at risk because of the Xenophobic whiny baby Leavers.
This may be on the smaller end of negative effects of the UK leaving the EU, but it is a microcosm of the bigger problem, and likely to get a disproportionate share of attention if The Doctor has to run, or Residue gets tossed in the trash, or other programs lose funding or find themselves operating in an environment of uncertainty.
It may also have nasty implications for science based research as well.
Yeah, but people don't care about that.
Sad but true.
Environmental regulations may be threatened.
Many of the leading voices for leave are denialists.
EU sponsored research would move to other countries.
On the other hand, David Cameron has secured for himself a place in (what's left of) British history.
What is it that Britain really needs to and must do concerning its political relations that it cannot do anyway in another, practically equally straight-forward, way? --provided that Parliament actually honors the wishes of the majority of voters in the so-called "Brexit" referendum