"So what explains the statements from Number 10 and from the trade secretary that, regardless of any circumstance, the transition period will end on 31 December 2020? The only possible explanations can be those two enduring features of government Brexit policy: ignorance and dishonesty. A trade deal cannot be agreed by 31 December 2020, and to contend that it can be either means you do not know what you are talking about or you are knowingly misleading the media and the voters. Over three years after the referendum, the government still has not learned key lessons of Brexit: of being realistic about what can be done, and about being honest about what is possible."
https://davidallengreen.com