Boris Johnson has set himself up to miss another Brexit deadline 

We are told that a vote for the Conservative Party is a vote to "get Brexit done". No more newspaper headlines about customs arrangements. No more mobile phone alerts about MPs ‘taking control of the order paper’. And no more Brexit battles to distract the government from issues like health and housing.  

The Conservatives have promised to take the UK out of the European Union on 31 January next year and would then use the 11-month transition period to agree the future relationship. The whole process would be over by 31 December 2020.  

It sounds simple, but the deadline is unrealistic – and unrealistic Brexit deadlines have a habit of coming and going. Just ask the Royal Mint, who are on their third version of the Brexit commemorative coin.  

Negotiating a future UK–EU relationship by December 2020 looks unlikely 

You can see why Boris Johnson thinks that deals can be wrapped up as deadlines loom. The UK and the EU have twice, in a matter of weeks, pulled deal-shaped rabbits out of hats. Most recently, Johnson secured changes to the Withdrawal Agreement – on the UK’s divorce from the EU – despite huge scepticism that he was capable of doing so. But this ignores both the extensive groundwork and ‘mapping exercises’ that went in advance of those breakthroughs and the large concessions that made them possible. 

When 31 January 2020 comes around, 34 months will have passed since the UK triggered Article 50 and began negotiations on the Withdrawal Agreement. The talks on the future arrangements will need to cover a far wider range of areas in just 11 months. And a chunk of that transition period could be lost as both the UK Parliament and European Council first need to sign off on their sides’ objectives. 

Conventional free trade agreement negotiations tend to take place over years, with regular breaks between negotiating rounds. It is possible to argue that around nine non-stop months of UK–EU talks (allowing some time for mandate approval) would represent equivalent time “in the room”. But gaps in negotiations allow each side to return home and lay the groundwork for any concessions or movement – and if Johnson leads the next government and wants any chance of getting a deal on future relations negotiated by the end of 2020, then he would need to make some big concessions. Tariff and quota free trade will come at a price – following EU rules and, most likely, a continued role for the European Court of Justice.  

The UK Parliament may prove to be an easier hurdle than the EU in ratifying a deal 

If talks succeeded and Johnson did get a deal on future relations by December 2020, then the ratification process would begin. The EU and UK have spent nearly a year attempting to ratify the Withdrawal Agreement, broken up by attempts to tweak and amend the deal. The UK side has proved endlessly problematic, and Parliament will need to pass primary legislation to implement the future relationship. But the big stumbling block might this time shift to the continent. National and regional parliaments across the EU27 would get a vote – and a veto. And it is a process which won’t be in the UK’s hands. Number 10 can’t, however much it might want to, play hard ball with the National Assembly in France.  

The process, which could take years, will cast a shadow over the talks. A deal has to be agreed and ratified by December 2020 or the UK will be facing its next no-deal cliff edge – the point at which arrangements covering everything except for the Irish border, citizens’ rights and the UK’s financial settlement will simply fall away. There is potential to provisionally apply parts of an agreement – which means the deal would come into force pending the full ratification process.

But agreement and preparation for provisional application is a process which can take more than a year and there will almost certainly be politically contentious parts of the deal which are not part of “EU competence”, such as intellectual property and other parts of services trade, and which cannot be provisionally agreed. The UK will – in practice – be facing a no-deal exit in those areas.  

Ratification is only part of the task – a deal still needs to be implemented 

Even in the unlikely scenario of pain-free negotiations and swift provisional application, the Brexit job will be a long way from "done". 

The UK will need to reflect thousands of pages of legal text into the systems and processes of government. Putting an agreed deal on the government website is one thing, updating customs technologies, immigration rules and changing the operating processes of arms-length bodies is another – much more time consuming – job. 

There might be a handful of officials negotiating at any one time, but the total number of UK civil servants expected to be working on Brexit by March next year is 27,500. The vast majority are preparing for what any agreement – or the absence of one – will mean in practice. And the full details of the deal are unlikely to be available until possibly days before the transition is due to end. 

Businesses and citizens will also need to adapt. Free trade agreements usually have an adjustment period of years, and the UK government will face both political and economic costs if it instantly brings in a whole host of new barriers to trade. 

Whatever the prime minister’s confidence in negotiating and ratifying a deal in just 11 months, he must realise that this is only the start of the job. Brexit does not end when a deal is done. It is likely to be years before the UK government and businesses have fully adapted to life outside the EU.  

A hard deadline on December 2020 only backs Boris Johnson further into the Brexit corner 

The prospect of the UK government being sure of hitting the December deadline in June 2020, when the process to extend the transition period must be concluded, is zero.  

This reality will face Boris Johnson as soon as the future relationship talks get underway. Breaking his promise on transition extension might give him precious extra time, but it will let down Brexiteers, infuriate Nigel Farage, and force the PM to agree further payments into the EU budget. His other option is attempting to push the EU and Parliament into a corner and hope to force a choice between ‘my deal or no deal’.  

However, past experience suggests that it is the prime minister who will find himself searching for a way out of another deadline dead end.