Tariffs are only 1 dimension of the costs associated with international trade. Non-tariff barriers matter & shouldn't be underestimated - from the cost of completing declarations to additional regulatory costs + adaptation of supply chains to mitigate delays (warehousing...) 1/
And I'm not even talking about training & recruitment costs, cost of stockpiling for multiple deadlines in 2019, consulting costs etc... which are perhaps more temporary. Also consider potential additional transport costs (drivers waiting time, restrictions making journeys... 2/
...less profitable for operators, etc). For customs alone, HMRC estimated in October 2019 that the cost of making declarations for UK businesses would be £7.5 billion. @jdportes @julianHjessop @lizzzburden @pmdfoster - hard to reconcile that with £8.3 billion savings figure /3 
And before anyone says:"ah, but easements will mitigate this cost" (which was indeed implied in the HMRC publication), we're told they're all being revised & will likely disappear... /END
