Corbyn may have supported the IRA when it was killing children on Britain’s streets; he may have counted the jihadists of Hezbollah and Hamas as his friends; he may be economically illiterate and a poor public speaker – but at least he could be relied on to stick to his principles no matter what.
Well, that narrative unravelled this week when Labour announced its latest ruse on Brexit – by my count at least the party’s 20th policy position since the referendum in June 2016. With a breathtaking spectacular backflip, Corbyn revealed that despite previously opposing staying in a customs union, he was now in favour of the idea, not just for a temporary transition period but for good.
This is a staggeringly bad policy that represents the worst of all possible worlds. We would have to obey the EU’s regulations, but have no say in forming them. And we wouldn’t be able to strike trade deals with countries around the world – one of the main benefits of Brexit – without the EU’s say so.
It is hard to overstate the scale of Corbyn’s U-turn on this crucial issue. He was one of an original band of Labour left-wingers who were implacably opposed to the EU, seeing it as a sinister capitalist conspiracy – a big businessman’s club as they called it – that was designed solely to exploit the working classes.
But while fellow Labour MPs such as Tony Blair and Neil Kinnock quickly abandoned their original Euro-sceptism, Corbyn remained a true believer in Britain’s independence from the EU.
Over the years, he has remained remarkably consistent in his opposition to the EU. He voted against membership of the EEC in 1975, against the Maastricht Treaty in 1993 and against the Lisbon Treaty as recently as 2009.
And although Labour’s official position was to Remain in the 2016 referendum, Corbyn was notably lukewarm about the idea and he ran a lacklustre campaign, which many believed contributed to Leave’s stunning victory.
So why the big change now? Why has Corbyn so easily shrugged off his cherished principles and deeply-held fundamental beliefs?
Has he experienced a sudden Damascene-like conversion to the benefits of a customs union, despite spending his entire career campaigning against it?
No, I don’t think so. Corbyn has too dull a brain for such mental gymnastics. He hasn’t changed his mind on a single issue since 1970.
The truth is far simpler – it is a very cynical political manoeuvre designed to put Corbyn in Number 10 Downing Street before next Christmas and completely derail Brexit.
We now witness the unedifying sight of Labour conspiring with the EU’s chief negotiator Michel Barnier to undermine the UK government’s position and topple Theresa May.
There are no high principles on display here – just naked political opportunism.
Far from being an example of that rare beast – a politician who remains true to his convictions – Corbyn is revealed as the most slippery of careerists with an eye for the main chance.
And he could be successful. The pro-EU Tory rebels, such as Anna Soubry, are in out and out kamikaze mode. They are prepared to see the UK go to ruin under Corbyn in order to save their dream of a United States of Europe. They should not be – will not be – forgiven.
The anti-Brexit plotters are playing with fire. Most importantly they are deliberately stirring up troubles over the Irish border to undermine Mrs May. But by doing so they are risking the peace process. And the last thing anyone wants is for Corbyn’s old chums in the IRA to restart their terror campaign.
Corbyn’s U-turn also represents a brutal betrayal of Labour’s loyal supporters who voted in their millions, particularly in the North, to throw off the yoke of the moribund EU.
Labour is, in effect, kicking them in the shins and telling them they are just too stupid to know what they were voting for.
A fascinating question is what will be the reaction amongst Labour’s core vote in the heartlands to Corbyn’s flip-flopping? Will they realise they have been betrayed and treated like fools?
I do hope so.