Of the many casualties of the crisis now besetting Labour and Tories alike, the worst is the absence of any intelligent debate about what a progressive exit plan from Europe might resemble.
I personally don't think the decision to leave can be fudged. The British public spoke loud and clear. The decision must be honoured. But there are now a million and one choices to be made about how a new very special relationship with the neighbours takes shape.
By wide consent, the crux of the challenge is this: how can we deliver the immigration reform the public wants, with minimum disturbance to trade? On this we all want certainty, so the faster we get some options for reform of free movement, the better.
The Leave campaigners put at the heart of their argument, a bold ambition for an 'Australian-style points system'. And so as the minister who spent two years introducing the points system for non-EU migrants between 2006-2008, I thought I might offer a few thoughts.
Let me start with a gentle word of warning. This ain't simple. Back in 2006, I faced a bewildering range of 57 different routes into Britain, each with its own rules and case-law that had grown up over the post-war years. So I tried a radical simplification; cutting 57 routes to just five, of which one - the low skill Tier 3 - was never introduced. But immigration systems are complicated because people are complicated - and so are the needs of business. So you end up creating lots of ways to earn the points you need to enter. For instance, when I thought about defining 'high skill' migration in terms of qualifications, I immediately had a problem with the Premier League who assured me that while top league footballers earned squillions of pounds of week, they were not over-burdened with PhDs.
Points or no points, the first decision the government has to make is whether to introduce a overall cap on numbers. My advice is 'don't'. Non-EU migration has fallen by about 10% a year since the points system was introduced and setting a total cap, means the government immediately sets itself up as a sort of Stalinist Bureau of Labour Planning with the Herculean task of figuring out just how many people every corner of industry is going to need for the years ahead. Australia tried it - but in the event had to invent ways round it, not least because they ran out skills in critical sectors (like hairdressers, as it happens).
So what are some sensible principles for reform? Here's five thoughts to get us started.
Focus on low-skill migration - and think about some tried and tested techniques. It doesn't make a lot of sense for a knowledge-intensive economy like ours to halt high-skill migration. So a better option to re-introduce the kind of 'transitional controls' we had for Bulgaria and Romania in 200. Known as the Worker Registration Scheme, it set an annual quota of visas for low skilled workers, employed by accredited employers. Using a tried and tested scheme of the type many European countries introduced after the expansion of Europe might help persuade our neighbours that we're not 'ending' the principle of free movement; but we are keeping a brake in place to help manage pressure on public services.
Allow free movement of students and scientists. Amongst the many lunacies in the migration debate played out every quarter, is the inclusion of students and scientists in the statistics. Free movement of ideas between Britain and the Continent has been instrumental in our development from time immemorial. The Enlightenment and the Industrial Revolution were amongst its fruits. So, free movement of scientists and students is a must if we are not to damage our precious colleges and universities or hurt the evolution of our knowledge economy; which, by the way, is where the best jobs are to be found.
Let British citizens fall in love with whoever they like. It's worth remembering that 'economic migration' never covers the full range of people arriving at the ports. And along with workers and students are spouses - the partners of British citizens who surely have a God-given right to fall in love with whoever they like. There were 38,000 (non-EU) family visas granted last year - a number which has fallen sharply as the government has introduced income and language tests for newcomers. It would make an awful lot of sense to do away with these rules for our closest neighbours.
Step-up to our obligations to refugees. If we are setting out to bring down the numbers of 'economic migrants', then surely there is a case for finally stepping up to our responsibilities to offer greater sanctuary. Europe is facing the largest movement of people since World War Two, in no small part to our collective failures in Iraq, Syria and Libya. Cities all over Britain are offering to take more families than the government will admit. Surely, now is the time to open our hearts and homes a little more. It is our duty - and our neighbours would thank us for it.
Create a proper route to citizenship for all. Once people, they should be allowed to earn their stay. Over the years, in countless debates, I've learned Britain is not a nation of Alf Garnett's. As Immigration Minister, I developed ambitious plans for earned citizenship - which the Coalition Government scrapped - based on some simple principles. If people work hard and pay tax, learn English and obey the law, after five years they should be able to apply for citizenship. If we ban this, we end up with the sort of 'guest worker' problem you see in Europe; communities who never integrate, because no matter what they don, they can never truly 'belong'. That is bad for one-nation politics, whatever your party badge. And we should start by awarding rights for the EU citizens already here.
These are simple ideas drawn from an awful lot of experience. But, the final lesson is this; if we want immigration policy to work, there's two more lessons I learned the hard way.
People move faster than public money. So communities with low cost housing inevitable encounter pressure on school places and the NHS, when newcomers arrive quickly. So, a Migration Impact Fund - worth hundreds of millions of pounds - is essential to manage migration well, not least for building houses.
But most important of all is something fast disappearing in Britain. A proper technical education system. When I introduced the points system, I also set up the Migration Advisory Committee (MAC), to advise on which sectors needed migration because skills were in such short supply. The idea was that when the MAC found shortages, it would put jobs on the 'Shortage Occupation List', but that was supposed to trigger a surge in skills funding for that particular sector.
This bit of the system, somehow never happened. Which is why we have the nonsense today of communities like mine with a massive employing workers from abroad, while in the streets around it, we have sky high unemployment. This government has shredded the further education, adult education and apprenticeship system. That is simply a recipe for employers demanding freedom to hire abroad.
I never understood why David Cameron promised to cut net migration to tens of thousands. It was never deliverable - and his failure helped spark the fall in trust, that provoked many to vote to leave. So if there is one thing we can salvage from this sorry story, let's try to make it sanity in the immigration debate. It is surely time to end, the way this touchstone issue poisons our national politics.
Liam Byrne is the Labour MP for Birmingham Hodge Hill