The European Court of Justice is an almost unknown institution which has suddenly taken on enormous political significance. For as Lord Ashcroft’s research has indicated, the main reason people voted for Brexit was not to reduce immigration but to “take back control”.

And taking back control turns out to mean leaving the jurisdiction of the ECJ. We have this on the authority of the Prime Minister, who last October declared to the Conservative Party Conference:

“Our laws will be made not in Brussels but in Westminster.  The judges interpreting those laws will sit not in Luxembourg but in courts in this country.  The authority of EU law in Britain will end… we are not leaving only to return to the jurisdiction of the European Court of Justice. That’s not going to happen.”

Her point has recently been reiterated by Jacob Rees-Mogg:

“It [the ECJ] cannot be our senior court for a day after we leave the EU. It is about control. Do we make our laws according to our own democratic principles on the day we have left or not? If we don’t, we are still in the European Union. That is the essence of the whole debate… the court must just stop on the day we have gone.”

But many doubts have been raised about whether this is really feasible. James Chapman, who used to work for David Davis, says that by taking such an “absolutist” position, Theresa May has “hamstrung” the British negotiators.

Piet Eeckhout, who used to work at the ECJ and is now Dean of Laws at University College London and Academic Director of the UCL European Institute, concluded a piece published a few days ago by declaring:

(1) that the UK had better not antagonise the ECJ too much, if it really wants to continue to cooperate with the EU, and (2) that one wonders how much is gained by formally leaving the Court’s jurisdiction.

The purpose of this profile is not to adjudicate on the rights and wrongs of the argument. It is to render the ECJ slightly less unknown.

For like other European institutions, it has avoided scrutiny by appearing impossibly dull and technical, the sort of place only a lawyer would find interesting. It has attracted less attention than the European Court of Human Rights in Strasbourg, with which the ECJ is sometimes confused.

No British editor has ever exclaimed, in a fit of excitement, “I want a profile of the European Court of Justice!” – or none until Paul Goodman commissioned this profile. While writing it, I could not help being struck by the fact that for most of the time, neither side sees, or even wants to see, the other’s point of view. As in the referendum campaign, each side is deeply emotional, but regards its own position as the only one a sane, well-balanced person could take of the matter, while the other side’s arguments are madly exaggerated and intolerably provocative.

The ECJ sits in Luxembourg, in a large collection of modern buildings, faintly suggestive of an art gallery, equipped with flagpoles carrying the flags of the member states, and situated on a plateau with a view over the old city. From the top of its bronze-coloured towers, four countries – Germany, France, Belgium and Luxembourg – can be seen.

It was founded in 1952 as the court for the European Coal and Steel Community, and from the signing in 1957 of the Treaty of Rome and the Euratom Treaty took on the same role for the European Economic Community and the European Atomic Energy Community. In the view of Hugo Young, who looked carefully into the matter for his magisterial volume This Blessed Plot: Britain and Europe from Churchill to Blair (1998),

“As early as 1963 [in Case 26/62, Van Gend en Loos v. Nederlandse Tariefcommissie]  the European Court of Justice pronounced that the Treaty of Rome had, among other things, created a new legal order in international law ‘for whose benefit the States have limited their sovereign rights’.”

Each of the 28 members of the EU nominates one judge to the court, which in the course of its history has had 11 presidents, including one Briton, Jack Mackenzie-Stuart, from Edinburgh, who presided from 1980-84. In an obituary of him for The Guardian, Lord Cameron of Lochbroom wrote of his eagerness to lead the ECJ

“into debate with members of the Supreme Court of the United States. This was to a Scots lawyer like Mackenzie-Stuart a rational extension of the principles of the age of enlightenment with which Scotland and Scots lawyers had been associated. He considered that in holding the balance between collective law-making through Brussels and the laws of the member states, especially in the areas of freedom to trade and work, the best way for the Court of Justice to secure that balance lay in a community-wide rule of law rather than the ‘subsidiarity’ of the Maastricht treaty. In 1996, he warned that the court functions as ‘a bulwark against the Balkanisation of western Europe, and we undermine it at our peril’.”

One may note here how reasonable, enlightened and balanced the work of the court appears to those engaged in its development. In a recent interview, the present President, Koen Lenaerts, who is from Belgium and is also Professor of European Law at the Catholic University of Leuven, sees the judges as so many “umpires”, whose work benefits everyone on the field of play.

According to Lenaerts, “After Brexit, there will be British firms begging our court to get ‘locus standi’ [the right to be heard in court].” He also predicts that if the EU imposes anti-dumping measures against Britain, “of course the UK Government will run to this court to ask for judicial review”.

But most interesting of all is the comparison which Lenaerts, who has long specialised in the comparative study of American and European law, makes, as Mackenzie-Stuart did, with the US Supreme Court:

“After the independence of the United States, 4 July 1776, it didn’t last long before the USA took a 180 degree opposite route than the Common Law basis that existed in the UK. And this on the crucial point, that lawyers know under the code name, Marbury v. Madison 1803, Chief Justice Marshall writing for a unanimous court at the time composed of five judges. And that ruling said that an act of Congress can be quashed by the Supreme Court for being in conflict with the constitution. And there you have it.

“In the United Kingdom, nothing of the sort exists. Because their paradigm is 180 degrees the opposite. Parliament can do no wrong. So an act of the parliament of Westminster cannot be quashed in a British court. This is comparative constitutional law – we should de-emotionalise all of this.

“So mentally, emotionally, it is in the British perception of the ‘triangle’ – representative democracy, rule of law, fundamental rights – unthinkable that a court can quash an act of parliament. This exists for 220 years in the US, that system, not in Britain.

“The European Union has the exact same system as the US. And for an obvious reason – the EU is united in diversity. The US motto is e pluribus unum – out of the many, one. So both systems are confronted with keeping the balance between unity and diversity, which is the proper picture of federalism. Often ill-understood in the UK, because federalism there is seen as something uniting, not federalism as something with Belgium – with us, it has exact opposite meaning. That is, that you empower all these regional governments, and keep the proper balance, like in Germany – the Bundeslaender etc. That’s also the balance of the European Union, like the balance of the United States.”

Eleanor Sharpston QC, the longest-serving British member of the court – she has served there as an advocate-general since 2006 – says the British common law tradition has enriched the work of the court:  “Some very good [UK] people have served in the court – Lord Gordon Slynn, Sir Konrad Schiemann [both appeal court judges] and Sir Francis Jacobs – and they have made a difference.”

Only after Britain joined in 1973 did judges start asking questions, instead of just listening, as is the French tradition. Sharpston points out that the ECJ does not decide national cases. It instead rules on points of law which have been referred to it by national courts, and by this method harmonises national legal systems.

As the EU’s competences have expanded, so have those of the ECJ. In February 2016, the court’s tendency to engage in “judicial activism” drew a fierce rebuke from a senior lawyer in London, Marina Wheeler QC:

“My thesis is this: the reach of the Court of Justice of the European Union in Luxembourg has extended to a point where the status quo is untenable. Aside from eroding national sovereignty, which it does, the current situation also undermines legal certainty, which in turn undermines good governance.

“To limit the still-growing reach of EU law, it is not enough to use ‘red cards’ to stem the flow of EU legislation. Reform needs to address the EU legal order, in particular the jurisdictional muscle-flexing of the Court in Luxembourg.”

David Cameron failed to obtain any such reforms, and as Wheeler went on to complain, the ECJ was now using the Charter of Fundamental Rights, proclaimed in 2000, to compete with the ECHR in Strasbourg, even though Tony Blair had been assured that the Charter would change nothing.

This attack on the ECJ was loyally taken up by Wheeler’s husband, Boris Johnson. It became one of the most powerful elements in the case he made for leaving the EU, and re-emerged in the Prime Minister’s speech last October.

But how easy will it be to leave the ECJ? Piet Eeckhout, already quoted at the start of this piece, contends, as others have, that co-operative arrangements with the EU in such fields as aviation, financial “passporting”, the European Arrest Warrant, recognition of judgments in civil and commercial matters (a huge issue, he contends, for a legal system which prides itself on being the place to go for international commercial contracts), Euratom and the movement of nuclear material, and international sanctions, all depend on accepting the continued “ultimate jurisdiction” of the ECJ.

Eeckhout goes on:

“The ECJ insists on the ‘autonomy’ of EU law being safeguarded in any dispute settlement arrangements [reached as part of a comprehensive Brexit settlement]. It has the tools to enforce this, particularly as any ‘envisaged’ agreement can be made subject to ECJ review on the mere request of any member state or EU institution. In recent years it is becoming established practice that any controversial agreements are first put to the Court.  There is no reason to expect that this will not be the fate of the Article 50 withdrawal agreement, or of a future deep and comprehensive agreement.”

The ECJ takes a very high view of its competences. The British Parliament and people likewise take a very high view of their perfect right to leave the EU, and therefore the jurisdiction of the ECJ. It is by no means clear how easy it will be to reach a reasonable compromise between these two views, in which each side feels the other is behaving outrageously.

In 1532, Henry VIII wished to have Thomas Cranmer, who looked with favour on the King’s matrimonial plans, made Archbishop of Canterbury. The Pope resisted, but gave in when Henry, supported by Parliament, threatened to cut off Rome’s payments from the English Church. One cannot help thinking any payments the UK continues making to the EU will in practice be conditional on reasonable rather than confrontational behaviour by the ECJ.