The sound of ideology slamming into a wall of reality is already echoing throughout Whitehall, says Martin McKee, as he unpicks some of the consequences of Brexit.

On Wednesday 29 March 2017, Sir Tim Barrow presented a letter from Theresa May to Donald Tusk, President of the European Council, notifying the European Union of her government’s decision to leave the European Union (EU). The basic facts of what happened are not in doubt. There is a photographic record of the event, the Prime Minister reported to Parliament that the letter had indeed been handed over, and Donald Tusk, clearly saddened by this turn of events, reported that he had received it. Almost everything else remains as unclear as ever.

First, is the process now irrevocable? The UK government seems to think so. Many others disagree. Second, will it be possible to conclude an agreement in the two years specified in Article 50? Again, the UK government thinks it will. Others, including almost anyone who actually understands the European Union, are sceptical.

Those seeking clarity were hopeful that they might find some answers in the long awaited White Paper on the Great Repeal Bill, trailed as a means by which the tens of thousands (the government concedes, in the White Paper, that it doesn’t know precisely how many) of pieces of UK legislation derived from EU law would be reworded to take account of the UK’s post-Brexit circumstances. They were largely disappointed. Crucially, there was no indication of how the Act would be worded, even though the government has had nine months to think about it. Instead, we are told that it is to emerge from a process of open discussion, which some may think strange given the Prime Minister’s usual obsession with maintaining control.

An uncharitable view is that the government simply does not know how such an Act might be written. This, certainly, would be consistent with the marked lack of detail in the White Paper and the fact that five of its pages are entirely blank, and a further five contain only a blue rectangle. Could it be that discussing which colour to use for the rectangles and which pages to put them on was a welcome distraction from the more complex task of deciding what the document might actually say?

Nothwithstanding the lack of detail, some things were made clear, even if they were either missed or, more likely, misunderstood by many Brexit supporters, by now ecstatic that Article 50 had been triggered, but who remained oblivious to the problems ahead. None were especially surprising, although they were clearly at odds with the impression given previously by ministers about escaping the clutches of the European Treaties and the European Court of Justice. Thus, all EU Regulations (those bits of EU law that have direct effect in Member States), Directives (which are transposed into law to take account of national circumstances) and Treaty Provisions will remain in force post-Brexit, although they may subsequently be amended or abandoned. Case law from the European Court will continue to be used to interpret cases arising in relation to laws originating from the EU post-Brexit. European law will continue to have supremacy where there is a clash with domestic laws enacted prior to Brexit.

All of these proposals are sensible. Indeed, it is difficult to envisage any practical alternative. However, they are emphatically not what supporters of Brexit believed would happen. Indeed, those MPs who believe that Brexit offers scope for a bonfire of red tape, including Jacob Rees-Mogg, who argued that environmental and safety standards that are good enough for India are good enough for the UK, must surely be disappointed as these areas are explicitly mentioned in the White Paper as areas where EU standards will be retained. Crucially, the EU has also stated that they are essential conditions for any future free trade deal.

What is more contentious is how the government proposes making subsequent changes to existing law. No doubt encouraged by Parliament’s vote to give it an entirely free hand in the Brexit process, it has now extended this principle to remove Parliament from its traditional role of making laws. Given the scale of the task, coupled with the expected disruption over several years caused by the proposed renovation of the Houses of Parliament, this may seem a pragmatic solution to allow MPs time to get on with other things, such as finding somewhere new to meet, but it does rather challenge the idea that the UK is a parliamentary democracy. Another area of contention is the lack of any concession to the devolved assemblies in Scotland, Wales, and Northern Ireland. Yet this simply continues the refusal by the Prime Minister to engage in any meaningful discussion about Brexit with the devolved administrations, leading them to see Brexit as a means to roll back devolution.

Then there are the practical problems. Many aspects of EU law involve interaction with one of the almost 50 specialised European agencies. Ciaran McGonagle, an astute observer of the Brexit process, uses the example of the Community Plant Variety Office to illustrate the challenge. This little-known institution, based in Angers, in France, is responsible for protecting intellectual property of plant breeders throughout the EU, including issuance of licences for those seeking to use protected products. Most attention has focused on withdrawal from the European Medicines Agency, which will have to move from London, will delay access to innovative medicines in the NHS, and damage the UK pharmaceutical industry. Public health professionals are concerned about the uncertainty surrounding our future relationship with, among others, the European Food Safety Authority and the European Centre for Disease Prevention and Control. The White Paper simply states that it might remove any requirement for the roles undertaken by these agencies or replace them with UK bodies. Quite where it would find the often highly specialised expertise required is unclear while, consistent with all its documentation on Brexit so far, there is absolutely no mention of the financial implications of doing so. A further concern is the UK’s stated intention to withdraw from the EURATOM treaty. This surprised almost everyone, given that our membership of EURATOM provides the basis for our nuclear power stations to operate safely. Again, health professionals have an interest, as leaving threatens our supply of medical radioisotopes.

So this new White Paper does go beyond what the government has said previously, albeit backing down from many of the more implausible suggestions that some pro-Brexit ministers have previously made. The sound of ideology slamming into a wall of reality is already echoing throughout Whitehall. But there is still some way to go, not least because we now have more detail of what that reality will look like.

This reality has come in the form of the EU’s response to the letter triggering Article 50. This serves as a reminder that Article 50 is part of an EU Treaty and not a British one. In other words, the EU determines the rules. The EU has made clear that, contrary to the UK government’s stated desire, discussions on future trade can only begin once there is significant progress on the arrangements for Brexit, including agreement on the sums that the UK owes to meet its existing commitments. It has rekindled arguments about the status of Gibraltar, something that came as a surprise to no-one except, it seems, the UK government and the tabloid press. And it has made clear, again to the surprise of no-one who understands the EU, that free movement and the role of the European Court of Justice will continue during any transition period, which could last rather a long time given the complexities involved.

Already, there is evidence that the UK is recognising this reality, backing down from its ill-advised threats to reduce co-operation on security, which would have created as much of a risk to the UK as its European partners. The bizarre suggestion that the UK could walk away from discussions and trade on World Trade Organisation terms also seems to have been quietly dropped. A recent analysis of the consequences for trade in lamb and mutton, seemingly one of the simplest issues, reveals the sheer complexity involved and the likelihood that any agreement could take years.

These events suggest that, at last, reality is, very slowly, beginning to dawn on some in Westminster. The challenge will be how to explain it to those who thought they could “take back control” that this was never more than a fantasy.

Martin McKee is professor of European public health at the London School of Hygiene and Tropical Medicine.