Once we exit the current transition period at the end of December 2020, businesses may have to pay tariffs to bring goods into the UK, depending on where you are bringing them in from.
The UK has always used the EU’s tariff system – the CET – to apply tariffs outside of the EU, but now it has one of its own – the UK Global Tariff (UKGT).
When trading with the EU the UK has always had zero tariffs, but if there is no free trade agreement with the EU signed by the end of December, the UKGT will have to be applied. Note, that some of these tariffs have been reduced to zero anyway (e.g. shrubs, outdoor plants, trees, unrooted cuttings etc).