Also, the U.K. paper isn't a negotiating document and presented technical ideas that weren't fully developed and lacked significant detail. The two long-term approaches "are worth exploring further, but the hard work of assessing whether these ideas could work in practice has yet to be done," wrote Thomas Sampson of the London School of Economics in a blog.

Related article

LSE Brexit blog

UK government’s customs position paper fails to answer key questions

The UK government’s new position paper on future customs arrangements sets out its objectives for how goods trade with the EU will be governed following Brexit. However, as Thomas Sampson from the LSE’s Centre for Economic Performance outlines below, the proposal is incomplete and leaves unanswered five key questions about the UK’s position.