The terms and conditions of the WTO fall-back option and the extent to which the WTO could act as a safety net for the UK’s future economic relations depend, to a great extent, on successful negotiations with all other WTO Members. There are significant differences between EU and WTO membership, in terms of the applicable trade rules and their economic impact, as well as compliance and dispute settlement procedures. Imposing new regulations and processes will inevitably entail additional costs and delays, regardless of any mitigation agreements. Finally, the EU-UK relationship covers much more than trade so the WTO fall-back option will in any case leave major legal vacuums. Thus, the mantra “no deal is better than a bad deal” is misleading; the WTO fall-back option falls far short of providing an adequate safety net, even for trade matters.
More information here.