The document, which was hand-written in black marker pen, was found in a minsterial Red Box left in a progressive Soho club, and explains in some detail the battle-lines that will be drawn by Labour as they fight for an unprecedented fourth term.
While the paper is currently being studied by graphologists to extract the detailed content from the PM's indecipherable heiroglyphics, The Diary can exclusively reveal those elements of the Manifesto which have already been decoded:
Eton College is to be subject to a new 'Toffs Tax' on admission fees, expected to raise approximately £47m which will be paid as a one-off windfall to benefit claimants and Labour Party members;
All Old Etonians will be made subject to a 'Toffs Rate' of tax of 96% of all income, earned or unearned. CGT and IHT breaks will be withdrawn for OEs as well.
Eton College is to be designated part of a new 'Axis of Toffdom'. All Old Etonians will be subject to Control Orders.
A re-elected Labour Government will drive forward in the 'War on Toffs' with a surge of 5000 troops sent to Windsor to effect regime change. A new Headmaster and Faculty will then be put in place, approved by the Government, with staff taken from schools scoring the lowest in their recent Ofsted inspections.
The Bullingdon Club is to be designated a 'proscribed organisation', and membership, past or present, will disqualify any person from holding public office or board-level positions in the private sector.
The right to trial-by jury is to be revoked in cases involving Old Etonians, and Parliament will debate the reconstitution of Capital Punishment for membership of the Bullingdon Club.
(a sub-clause in the manifesto indicates that this legislation would be made retrospective in the cases of Boris Johnson, George Osborne and David Cameron).
A new charge of 'Being A Tory Toff' will be introduced, which will mandate severe sentencing for repeat offenders.
ASBO's to be issued to any young person seen wearing formal dress in the Slough and Windsor areas.
The ban on hunting with hounds will stay in place. However, a re-elected Labour Government will introduce an amendment to the Hunting Act which will permit the capture and subsequent hunting of 'Tory Toffs' through council estates by chavs with pit-bulls.
The remaining parts of the Manifesto are largely illegible, but seem to descend into a tirade about how 'it's all the toffs, we hate Tory Toffs, kill the toffs killthetoffstoffstoffs toffs itsalltheirfault,killthemkillthemclasswarkillthetoffsnomoretophatsThey'lltakepowermypreciousssstoffsetonianswehatethemwehatethem" before a urine stain renders the remainder unreadable.
We approached an Old Etonian for comment, but he beat us with his cane before screaming, "get thee gone, peasant!" as we hadn't doffed our caps.
More details on the Labour Party 'We're Not Toffs' Manifesto will be released once editorial staff at The Diary can control their laughter.