Thoughts on the Lib Dems wanting the UK to join a customs union with the EU, in order to boost the economy, thus raising more tax revenue for public services?
>A far more ambitious trade deal with Europe, including a new UK-EU customs union, would be the single biggest thing ministers could do to boost growth and fix the public finances.
https://www.libdems.org.uk/press/release/lib-dems-urge-labour-mps-to-back-closer-trade-with-eu-which-could-raise-pound25-billion-a-year-and-avoid-welfare-cuts

Unironically I think it's sensible. Britain is currently skint and our economy is hardly growing. Trading more with our European allies is sensible.