The UK and EU agreed a Trade and Cooperation Agreement (TCA) on Christmas Eve. This was passed by the UK Parliament on 30 December and took effect at the end of the following day as the UK left the single market and customs union at the end of the Brexit transition period (also known as the implementation period). While the agreeing of a deal (even a fairly limited one) has been widely welcomed, the rushed process, requiring businesses to adopt new ways of working at a few days notice, has faced criticism.