The German Constitutional Court ruled that the European Central Bank (ECB) public assets purchases programme ultra vires, meaning it was acting beyond its legal power. This has been the cornerstone of the “whatever it takes” approach to preserve the euro set by the bank’s former president, Mario Draghi. Before that, the German court took another extraordinary step.

It disregarded the judgment of the ECJ that validated the ECB decisions by labelling such a decision as ultra vires too. In its view, the ECJ manifestly went beyond the acceptable standards of legal interpretation.

In a single decision, two blows have been struck at the heart of European integration: its common currency and the primacy of EU law.

But according to a recent report by businessman and former director of Vote Leave Daniel Hodson, the move also clearly underscores on sovereignty, constitutional and accountability grounds – the reasons for the UK’s decision to leave the bloc.

In a report for Foundation for Independence, Mr Hodson wrote: "In summary the GCC found that a hugely significant part of recent ECB monetary activities – some €2.2trillion (£1.9trillion) of bond purchases – had no legal authority, negating an earlier ECJ ruling.

"It was saying in effect that whatever the ECJ might rule, if that were against the German constitution, the latter was sovereign, and the ECJ subservient.

"And the German constitution, at least for Germans, is immutable."

However, Mr Hodson noted, the problem is of course that, in strategic terms, for the development and protection of the EU’s journey towards ever closer union, the absolute and final authority of the ECJ is critical.

And yet there is a massive fissure in the "still developing constitutional structure of the EU", drawing further attention to its lack of accountability.

He added: "How could such a massive activity have been allowed to occur without political or legal scrutiny until now, many years after the event? How can such a key institution as the ECJ command such limited respect whereby some of its rulings can be subject to rejection by mere national courts, albeit of the highest standing?"

Analysing the nature of the British uncodified constitution, Mr Hodson claimed it has no comparator on the Continent in durability, depth and flexibility.

He noted: "It reflects the British view of democracy, transparency and accountability, as well as the Anglo-Saxon tradition of freedom of speech and action unless forbidden by the law, as opposed to permissible only as allowed by the law.

"At its heart – and the cornerstone of the Brexit movement – is the sovereignty of Parliament, which, were Britain to remain an EU member, would be slowly ceded to its institutions, including the now tarnished ECJ.

"The irony is that the British people would have been denied, for at least some of the ECJ’s rulings, the right of rejection now so clearly provided to Germany by its GCC."

The prominent Brexiteer concluded that the GCC judgement not only serves a reminder of the "constitutional mess" Britain is leaving behind, but also of the continuing and growing opportunities to change the ultimate shape of our exit terms.

He explained: "This judgement is an expensive warning and reminder of several to date under-recognised but potentially highly damaging aspects of the Withdrawal Agreement: the ECJ’s continuing and open-ended role as final court of appeal for the rights of EU nationals resident in the UK and for cases relating to EU law applicable in the UK prior to Brexit, as well as its possible future oversight of British Government state aid initiatives anywhere in the UK, because of their possible impact on Northern Irish activities, under the NI Protocol.

“And of course there is the ongoing EU insistence in the Brexit negotiation on level playing field regulatory requirements, final arbiter the ECJ – naturally – firmly rejected to date by the UK.

"Yet the Withdrawal Agreement, although a treaty, could still be amended by negotiation.

“Despite manifest current difficulties there is still time before December 31 to reduce substantially or eliminate the hamstrung ECJ’s lingering presence in the treaty underlying Brexit.

"Let’s salute those wise German judges and go for an even better Brexit.“