This article says that the UK might be willing to sign up for a youth mobility scheme with the EU (for 18-30 year-olds) because it could boost economic growth: “by some estimates, it could do more for growth than planning reform and housebuilding combined”.
However, the article also says that the UK government thinks it would be a mistake to get too close to the EU, because this could serve the narrative of right-wing populists:
Downing Street believes that part of the appeal of both Trump and our homegrown [British] strain of rightwing populism lies in how institutions like the EU became too detached from the people they were meant to serve. In short, [the UK government is] determined not to be seen defending the status quo.
Thoughts?
Customs union and single market aren’t the same thing. Customs union means no tariffs, and a unified tariff policy on those outside the union. Nothing more, nothing less. There are active discussions about doing this.
Single market is joining the EU, with regulatory alignment and free movement, as you quite rightly say.