I do not think we need a so called transition period after end March 2019. Its time for our overpaid CEOs to prove they are worth their huge salaries. Any fool can just run on with the current rules for a couple of years and collect their big salary and bonuses. The problem is they will want this extended to 3, 4 or more years. They will take the easy option if HMG does not make it clear they have to get on with it.
All we will be asking is for them to use WTO rules instead of EU rules. Most trade done by these FTSE multinationals is outside the EU and is already done on WTO rules so where is the problem? As Liam Fox points out frequently as we already conform to EU rules for our EU trade so that should also be an easy trade deal to do except of course for the BBC's economic journos. who see difficulties behind every lamp post.
Like us all these FTSE CEOs will do only the minimum amount of work they can get away with. Activist shareholders are few and far between and FTSE executives all sit on each others boards as non-execs anyway.
Remember Parkinson's law, "work expands so as to fill the time available for its completion". So it will be with UK companies if they are given a transition period of any length.
You see the same phenomenon with government and military contracts which are particularly prone to this effect. The more Generals are involved the longer things take. I used to advise them to buy off the shelf solutions but there were no Knighthoods down that path only economy and efficiency.
There is also Parkinson's law of triviality which is C. Northcote Parkinson's 1957 argument that members of an organisation give disproportionate weight to trivial issues. He provides the example of a fictional committee whose job was to approve the plans for a nuclear power plant spending the majority of its time on discussions about relatively minor but easy-to-grasp issues, such as what materials to use for the staff bike shed, while neglecting the proposed design of the plant itself, which is far more important and a far more difficult and complex task.
This law is about to come into its own with the near 400 amendments that our MPs have tabled to the Brexit Bill. Very few of these amendments will improve the Bill most are simply wrecking amendments designed to stop what we voted for in June 2016 .but we should end up with de luxe bike sheds for MPs.
MPs love trivia. It saves them having to think about the real issues. The only solution is to get rid of MPs and go to a direct democracy.