[ninalanyon]

Not all EU countries are in Schengen so why would the UK have to be part of it if it rejoined the EU?

[inigyou]

I thought it was a requirement now. The UK got special treatment because it was a founding or very early member of the EU, but now if it wants to rejoin it'll have to join on the same terms a country like Ukraine would.

[markvdb]

It's part of the package now. The same thing with the euro for example. New member states are supposed to adopt the euro at one point.

[wat10000]

The EU really wants all members to be in Schengen. The UK was allowed to opt out because its membership was so desirable. After the Brexit fiasco it's unlikely that the EU would want them back in so badly that they'd accept another opt-out.