I'm the Brexit expert who predicted it wouldn't happen. Now I'm certain I was right

Since the EU Referendum result in 2016, virtually everyone believed that Brexit would happen unless somehow it could be stopped by MPs on the opposition benches or through strong public pressure. Almost nobody thought the government would fail to deliver on its promise to make the UK leave the European Union collapsing under the weight of the enormity of this task.

That is, except for me. More than three years ago, I became known worldwide as the "expert" on Brexit who claimed that "Britain will never leave the EU".

My view was simple: there were 83,000 or more EU laws. Two years was an impossibly short time frame in which to form a definitive view about which of these should be kept, amended or repealed. And such a view would be necessary to form a viable vision for how Brexit would work in practice beyond empty campaign slogans. To "take back control" there needed to be a concrete perspective about what this means in practice.

And my view has come closest to getting this confusing Brexit saga right.

While many might hope the government's plans for Brexit might be prevented, my argument was that these plans were simply not up to the complex task of implementation. For example, how could we increase border controls for the UK overall, potentially diverting from the Common Travel Area, while maintaining no controls at all along the border in Northern Ireland? This clash should have been obvious a mile away, but it wasn't spotted by a Conservative political elite that routinely forgets about Northern Ireland. (In the current UK citizenship test handbook, immigrants must know how to contact the House of Commons, Welsh Assembly and Scottish Parliament, yet Stormont was apparently forgotten.) Solving this border clash is all the more difficult because the government has said nothing more concrete than it wishes to diverge from EU rules, but fails to say how it wishes to do so. A crucial missing piece in this jigsaw if any way forward is to be worked out.

My position has not been popular – or, at least, it wasn't at first. Most doubted I could be correct given the repeated reassurances May gave the public that she would deliver Brexit. Since she left office, to quote her famous words, we can say "nothing has changed, nothing has changed" under Boris Johnson either. Like Theresa May, Johnson offers similar promises that can't and won't be kept.

A superficial difference between May and Johnson may be thought to be the latter's sincerity. Certainly, Johnson knows his political legacy rests entirely on the imminent enactment of Brexit in some form – even if his "new" deal is little different and even worse than May's in weakening our rights and protections. Yes, parliamentary arithmetic was not on Johnson's side. But neither is his government's true commitment to Brexit. If they were truly so earnest in scaring the EU with a deal or no deal outcome, then why was virtually all Brexit preparation funds spent on advertising campaigns instead of actually getting people and new policies in place?

If Brexit by any name so important to delivery, what explains the failure to compromise by May or Johnson to get something – anything – passed?

Far more time and energy has been spent searching for scapegoats to blame for the government's failure to deliver Brexit than in getting bogged down in ensuring it did happen. We can only conjecture as to why this is the case from one prime minister to the next – and I believe will remain the case, December general election or none. Perhaps it's in the knowledge that any Brexit will damage the economy and that government would be punished at the polls for it afterwards. Or maybe it's in the hope that either a lost court challenge or if the EU did not agree an extension they could be criticised for blocking a referendum result that May and Johnson have little genuine interest in seeing happen.

We might never know their reasons but there are serious questions Leavers should ask themselves about the sincerity of this government in doing what it says. After all, Johnson is not best known for his veracity and there's little evidence that I can see that anything has changed now.

If we take anything away from the last three long years, we shouldn't mistake repeated reassurances that Brexit will happen as evidence that these promises won't be broken. As long as impossibly short time scales for enacting massive, complex legal changes remain in place, Brexit is no more likely to happen now than when Article 50 was first triggered. There was no plan at the start and little, if any, progress made since.

Not only do I further predict no Brexit before Christmas, but I expect we'll still be in the EU for some time to come at the rate we're going now.

Thom Brooks is a professor of law and government at Durham University