Over the cliff edge and on to the rocks below

• ? If Brexit negotiations were to break down, the UK would face a significant increase in trade disruption from March 2019, even if it were able to put some basic trading arrangements in place. In a scenario where key sectors face extra friction, we find that the level of UK GDP would be 2.0% – or £16bn in cash terms – lower at the end of 2020 compared with our baseline. The impact on the remaining EU countries, including Ireland, would be much smaller .
• ? This article focuses on what a cliff‐edge Brexit means for trade costs and prices. This is only part of the equation – such a scenario would also influence supply chains and migration, while there is also potential for policymakers to mitigate some of the negative effects via looser policy.
• ? The notion that the UK could simply walk away from Brexit negotiations and rely on WTO rules to trade with the world is deeply flawed. The UK would need to re‐establish more than 750 very complex international arrangements just to maintain the status quo. We expect only the most critical issues – such as air travel – to be resolved by March 2019. Exporters also face a substantial increase in non‐tariff barriers.
• ? A breakdown in talks would also see both sides levying tariffs on imports from each other from March 2019, raising the cost of importing UK goods into the EU by 3.5% and by 3.1% for goods imported into the UK from the EU. For the UK, this will apply to roughly 60% of its goods exports and imports, but for all EU countries except Ireland the share would be less than 10%.
• ? The additional trade frictions would knock around 1pp a year off UK GDP growth in 2019 and 2020, resulting in a period of very weak growth. And the risks to this scenario are skewed to the downside – a slump in confidence or failure to establish the necessary customs infrastructure in time could easily generate a worse outcome