It's also a Friday. I do wonder, actually, how the occasion is going to be marked - in TV terms that is; is it going to be all live feeds of Big Ben for example as the clock ticks to 11pm? Or will it just, you know, happen?
All in a very boring un-Big Breakfast way I imagine sadly, Channel 4 has rather lost its ability to be as cheeky as it was in the 90's - I imagine the stations will all do something or other but BBC will probably have a special Politics live, ITV might run a special Preston. Channel 4 is maybe an outlier, they could have a Last Leg special on that night, which is about as close to Big Breakfast as C4 gets these days.
But if they did have a BB on the week running up then I would probably have a tongue-in-cheek celebration of Europe. Ie. France day, Poland Day, Germany Day ect. Have a family of the day that has at least one relation hailing from the European country of the day and specially themed games/segments (assuming there was budget for that). Maybe even have a all-party-leader duke out with pies or something. Basically take the P but mostly in a "it's all rather stupid" sort of way rather than taking a side per-se.
But I don't know if I really recall BB being all that political. They'd look at the Papers and so on but they'd maybe at best comment or joke about the big stories and everything seemed to be fair game unless it was like super serious (in which case it was generally restricted to the news updates).