The argument runs that, by following this course, he hopes to destroy Theresa May’s government and move into No 10 himself.
It’s Monsieur Barnier, of course, a former French government minister, who is a thorn in Mrs May’s side, having preposterously proclaimed that Britain will have to pay a £50billion divorce settlement.
Jeremy Corbyn voted for Britain to leave what was then the Common Market in 1975. He then opposed the Maastricht Treaty that, 25 years ago, significantly extended the power of Brussels and laid the foundations for the EU becoming a superstate as it removed sovereign powers from individual member governments
Although many Tory Brexiteers detect a conspiracy between Corbyn and Brussels bigwigs to undermine Mrs May, I believe they have badly misread the intentions of the Labour leader.
But, as some in the Tory party traitorously plot against a gravely weakened PM amid irresponsible talk of possible successors and stalking-horses, the truth is that Corbyn could well make a vital contribution to the Brexit negotiations.
Although I’m not a big supporter of David Cameron, he deserves praise for being loyal to his successor by speaking out in favour of economic austerity.
His dignified conduct compares well with the rank disloyalty of some former prime ministers (Edward Heath springs to mind).
His backing of Theresa May is also a standing reproach to his shameless friend George Osborne, who is still fighting old battles and treacherously lobbing hand grenades daily at Mrs May.
He is on record in recent months as having said the referendum result was ‘a clear vote’ and has stressed his determination to get a ‘good deal with Europe’.
Indeed, currently the most popular politician in Britain — with a YouGov/Times poll yesterday giving Labour an eight-point lead over the Conservatives — he feels he has an increasing amount of authority to ensure Brexit happens.
There is a bigger irony here. In last month’s General Election, thousands of Remainers voted for Labour in the hope that if elected PM, Corbyn might overturn the referendum result or instigate a second vote.
The fact is that, at heart, Corbyn is much more critical of the EU than Theresa May — or many other members of the Cabinet.