Manifesto blame game underway as MPs and activists debate the winners and losers from a sensational leak

Labour has been convulsed by debate today over the contents of its leaked election manifesto. As the party awoke to drafts of the document splashed across several newspapers – both sympathetic and hostile – an intense discussion followed over who had leaked it, their motivation and the impact.

The manifesto set out a series of radical reforms, such as rail and Royal Mail nationalisation, that would amount to a reshaping of the British economy and public services. To Corbyn’s allies it was a plan to break the neo-liberal consensus and deliver a fairer economy and, to his opponents, it was a series of backward state intervetions that could be compared to the 1983 manifesto presided over by Michael Foot.

The 43-page document was ultimately examined and approved unanimously at the Clause V meeting in London today which was attended by up to 80 senior figures from the labour movement, including the shadow cabinet, members of the the national policy forum and the national executive, as well as trade union officials. This large group is not believed to have received full copies in advance of the crunch session in London today.

So who might have leaked it, and why? Several pundits pointed the figure at members of the shadow cabinet – but most members of the top team would only have been shown the sections relevant to their portfolio, rather than the whole document. This followed the procedure used when Ed Miliband was Labour leader.

There are several theories in circulation, which were outlined briefly by Tom Baldwin, a former media advisor to Miliband, when he appeared on the BBC’s Daily Politics today:

Someone trying to undermine Jeremy Corbyn – the contents of the document were revealed early, possibly by someone in Labour headquarters, in an attempt to make clear the leader’s vigorously left-wing agenda in the hope that he would be forced to backtrack.

A former Corbyn spokesman, Matt Zarb-Cousin, who remains loyal to his former boss, blamed Labour staff for the leak on Twitter last night.

Hearing the whole manifesto has been leaked by Labour HQ. Helpful of them to continue their tradition of undermining the leadership.

— Matt Zarb-Cousin (@mattzarb) May 10, 2017

On the plus side, the manifesto sounds banging and the final draft will be even better. Most transformational programme Britain’s ever seen

— Matt Zarb-Cousin (@mattzarb) May 10, 2017

However, despite tensions between party staff and Corbyn’s team, Labour officials are a dedicated team, who have worked under several leaders, and no evidence has been produced to support the claim. One insider told Politics Home that headquarters did not possess the document.

Someone who wanted to back up Corbyn – by putting out details of the policy-rich platform, just hours before Labour’s Clause V, it would have made it far harder for the up to 80 MPs and officials attending the discussion to row back from any of the proposals. In the end the manifesto was approved unanimously with “amendments”, Corbyn said, showing that a meeting room ratification is far less newsworthy than the drama of a leak, which blew out several newspaper front pages today.

Sources close to the leader have, however, categorically denied any suggestions they were behind the leak. And, given the fact the document was voted through today, one can say – with hindsight – that there was little need for them to distribute it early.

Someone trying to create the impression that someone is working against Corbyn – this is perhaps the most wild of the suggestions and works on the basis that an ally of the leader wanted to make it look as if the party was trying to undermine the leader, paving the way for a post-election clear-out of staff deemed to be unsympathetic.

No evidence has been produced for this view, however, and aides to Corbyn strongly denied a leak today.