Eurotunnel have now stepped in to the customs row (HERE) with a warning, this time in public, that they have been giving to ministers for "months". It's about the extra costs and delays on both sides of the tunnel with either of the two new customs proposals - even if the EU have already dismissed them anyway! The logic is irrefutable. The can't even begin to design the systems needed until the EU and the UK have reached a legally binding agreement on the future relationship. And while in The Guardian article, Eurotunnel talk of this being agreed sometime during the transition period, most commentators think it will be years away.
Even if by a miracle, we manage to get it all ratified by 2021, they will need time to design, build the system and the infrastructure, install, test and commission it, recruit and train staff and advise users in this country and the EU on how to operate it all. This is a massive task, at least three years or more and there is no way we could have a fixed end date due to the risk of missing it and chaos resulting.
In practice it is impossible to think of breaking completely free of the present customs union or the single market until about 2025 at the very best. In between there will be a general election and who knows what that will bring.
