Here is the new poster the Conservatives have just released, attacking Labour's financial links with Britain's largest trade union, Unite.
It's part of a fierce assault on the union this morning, with the Tories also launching an attack document on the subject and Michael Gove delivering a speech on "Charlie Whelan's new militant tendency".
The Tories aren't wrong to point out Labour's increasing financial dependency on the unions. Last year unions were responsible for 64 per cent (£9.8m) of all donations to the party, with Unite alone accounting for 25 per cent (£3.6m). But isn't this all rather nauseating, coming from a party that for so many years was sustained by the non-domiciled Michael Ashcroft?
As I've argued before, there is no comparison between the donations Labour receives from Unite's political fund (to which nearly 1.3 million members voluntarily contribute) and the millions the Tories receive from Ashcroft, a man who has sat in the legislature for nearly a decade without having the decency to become a full UK taxpayer.
Gove's claim that Labour's political strategy is now dictated by the unions isn't much more convincing. Here's a key passage:
Class warfare has not only been resurrected; it has been elevated to holy principle, used in every possible circumstance including, most famously, in vicious, aggressive and direct attacks from a prime minister who purports to govern in the national interest.
His description of Gordon Brown's rather amusing joke about "the playing fields of Eton" as "vicious, aggressive and direct" is absurd and delusional.
The party's decision to list the 108 MPs who belong to Unite, as if this proves that the party has been infiltrated by a hard-left sect, is equally laughable. It ignores that almost every Labour MP is obliged to belong to a union (after all, the party was founded by them).
Thus, ludicrously, Alan Milburn is at once "outed" as a member of Unite, while also being cited by Gove as a New Labour reformer who has quit parliament in horror at the rise of the unions.
But the Tories, for whom the looming British Airways strike is a political gift, aren't concerned with such objections: they've got an election to win. And today, buoyed by the latest polls and the European Commission's criticism of the government's deficit strategy, they've put Labour on the back foot for the first time in weeks.
Labour should respond not only by pointing out the contradictions I've outlined, but also by arguing that the Tories are rather more vulnerable to the charge of offering policies for cash.
As my colleague James Macintyre pointed out last year, a number of major Tory donors stand to gain more than £500,000 each from Cameron's plan to slash inheritance tax. Labour now needs to go on the attack -- and soon.