The trade agreement, negotiated under increasing time pressure due to the end of the transition period on 31 December 2020, had to address all of these issues.[10] Formal trade negotiations, in which Michel Barnier represented the EU and David Frost represented the UK, began on 31 March 2020. They were originally due to be concluded by the end of October 2020.[11] However, negotiations continued[12] and formally ended on 24 December 2020 when an agreement was reached in principle after ten negotiating rounds.