And the "leftwards" tag provides defenders of that orthodoxy with a handy label to apply to anyone, irrespective of the direction they wish to travel, who challenges the existing norm. "Leftwards" is often used to mean not only "extreme" and "unrealistic" but "backward-looking" as well.
Much of the commentary on the new Corbyn leadership, even from apparently neutral sources, has used the language in this way. In both the abbreviated form of the news bulletins, and in the longer "think pieces", the Labour Party is portrayed as having taken a significant step to the left.
To be fair, Jeremy Corbyn - for at least much of his political career - might well have claimed and relished such a label. It is certainly the case that much of what he has said and done in the past, and during the leadership campaign itself, might properly be described as left-wing.
But to treat his accession to the leadership as signifying simply a "lurch" leftwards is to give seriously inadequate attention to many of the ideas and policies he has now introduced to the public discourse.
Much of what he said in the leadership campaign - and much of what clearly resonated with large numbers of voters - is certainly at odds with current orthodoxy but is not intrinsically left-wing. It is increasingly seen as a natural response to the obvious failures of that orthodoxy.
His campaign clearly appealed to that growing number who are disturbed by increased poverty and widening inequality, who understand that we are a weaker and less successful society when we treat so many of our fellow-citizens as worthless, who agree with the OECD that inequality is not the price we must pay for economic success but is a major obstacle to it. They see these insights as both rational and ethical starting-points for an overdue and sensible attempt to tackle these issues.
They will be surprised to be told that what is to them a common sense response to what they see around them is a "lurch" anywhere, let alone leftwards. Are they moving "left" when they conclude, with the IMF, that austerity is a destructive and ineffective response to recession, that if qualitative easing is needed to rebuild the banks' balance sheets it might also be helpful if used to promote productive investment and employment, that economic policy should be made by elected and accountable governments and not by banks pursuing their own commercial interests?
The common factor underlying all of these attitudes and sentiments is not their "leftwards" direction, with all its connotations. Some are "left" in one sense or another, others merely common sense. They are linked principally by a common belief that - if the market always prevails - there is no role for democracy. The whole point of electing a government, after all, is to ensure that the harsh doctrines of the "free" market are moderated in the wider interest. Corbyn's message is that, while the market serves the powerful, government serves everyone.
His appeal to the voters is the best evidence so far that the "free-market" hegemony that has held us all - and not least Labour politicians - in thrall for so long is now on the wane. Corbyn's task now is to show that he will not head back into an old left laager and will not require the wagons to be drawn up in a circle. Instead, he must combine old and enduring values with a new conviction - supported by credible and workable policy - that the power of government can and must be used in the common interest.
He has already made a good start. He has taken good advice and earned support from leading economists who are beginning to build the new mainstream.
In New Zealand, we have the luxury of being able to escape the British preoccupation with labels. We can overlook some of the skeletons supposedly in Corbyn's cupboard while focusing on and applauding his new policy initiatives.
Bryan Gould is a former UK Labour MP and former vice-chancellor of Waikato University.
