Almost exactly a year ago, announcing the commissioning of a report by his economic adviser, the Eurosceptic banker Gerard Lyons, on the pros and cons of remaining in the EU, Boris Johnson gave the Daily Telegraph his initial thoughts on the matter.
He wrote that leaving the EU would be detrimental for foreign direct investment, would cut us all off from the biggest market in the world, make us unable to write its trading rules and would make us far less powerful in the world in trade and diplomatic terms.
Boris then went on to list the advantages of Brexit. Surprisingly the biggest one, in his own words, is that if we left the EU we would have to finally confront the fact that most of our problems are not caused by Brussels but by "chronic British short-termism, inadequate management, sloth, low skills, a culture of easy gratification and under-investment in both human and physical capital and infrastructure."
Why, the Mayor wanted to know, are we still so much less productive than the Germans? The answer, he intimated, "has nothing to do with the EU. In or out of the EU, we must have a clear vision of how we are going to be competitive in a global economy."
Now on the eve of the Lyons' report Boris has changed his tune: unless major reforms are achieved, he warns, the PM has to be prepared to campaign to take Britain out.
Yet the leaked extracts from the report do not offer a substantially different analysis than the Mayor himself was able to provide a year ago. The UK is better off in a reformed EU, we are told, although London could eventually do as well, if not better, if we were outside an unreformed EU.
I supposed the first question needs to be: Which reforms? For a substantial percentage of outers no reform will be good or big enough - they want Britain to leave, whether it ends up being richer or poorer, more influential or more isolated, because any other outcome is preferable to them than staying in.
There is then a second question: Do we pitch our reform efforts at a realistic level, to achieve a concrete result within the EU or do we issue empty ultimatums to give ourselves the political cover to leave, as the Mayor now seems to imply we should do?
Thirdly, in whose interest are we thrashing out a future deal? Is it just the City, with its freewheeling, bonus-loving bankers, or the country at large - its manufacturers and hoteliers, its academics and scientists, its small and medium size enterprises and its universities, its farmers and its digital entrepreneurs - the bits of the economy in other words that cannot so easily cut themselves off and become floating little Singapores, but need a living, breathing country and continent to work and prosper in?
Now let us take the completion of the Single Market, one of the eight points for renegotiation allegedly raised by Lyons in his report. We at British Influence would agree wholeheartedly with that aim, as would many of Britain's allies in Europe. In fact, all EU leaders explicitly signed up to that and many other reforms in the Strategic Agenda at the end of the June EU council.
But what if it takes serious diplomatic work rather than a series of impossible demands? Are we willing to stick around, work with our allies in Europe, put pressure on, cajole and persuade those few who still need prodding and convincing, for as long as it takes until every member state is on board and reform is achieved?
Boris says he has no doubt Britain can lead a campaign for reform - his warning is that we can only achieve that by carrying a big stick: our exit from the club. But this is not a zero-sum game. Gaining a series of special concessions just for us 'or else we leave' isn't winning friends or influencing people. The EU, reformed or otherwise, will carry on existing next door to us for the foreseeable future.
A real win would be for the EU to become better, less bureaucratic, more focused on growth and jobs. To get that we need to be in an altogether longer game, one in which a more useful perception of Britain's position might be that we are willing to stick it out, not to abandon ship at the first opportunity.
The facts on the ground have not really changed from Boris' initial assessment of the pros and cons of membership last year. Maybe we are just one year closer to an election in which Boris needs to position himself as the tough-talking Eurosceptic reaching out for an uncompromising deal.
His or anyone else's ability to get a deal that would please the Europhobes in the Conservative Party, and whether the UK would really be better off if it chose to walk away from the table instead, is still highly debatable.