Do you believe this man? Leader of the Conservative Party David Cameron during his Election launch speech at County Hall, Westminster, Tuesday April 6, 2010. Photo By Andrew Parsons

This general election – as many elections do – hinges on credibility: Do British voters believe that Prime Minister Gordon Brown can continue to lead Britain?

And more importantly, do they believe that the Tories have actually changed

“…it is hard to see why election manifestos should be taken seriously.”

, from the party of the rich to a party that can represent everyone?

Despite the cautiously positive reviews on many paper’s editorial pages, there was no dearth today of people who don’t believe that the Tories have changed.

J.K. Rowling, author of the immensely, hugely, sun-blottingly popular Harry Potter series, for one. In an op-ed entitled “The single mother’s manifesto” in The Times today, Rowling explained that when she and her husband divorced in 1993, before she was a published author, she became a part-time teacher and single parent living off benefits, a “hate figure to a certain section of the press, and a bogeyman to the Tory Government.”

“David Cameron tells us that the Conservatives have changed, that they are no longer the ‘nasty party’ … but I, for one, am not buying it,” Rowling wrote. “He has repackaged a policy that made desperate lives worse when his party was last in power, and is trying to sell it as something new. I’ve never voted Tory before … and they keep on reminding me why.”

Seumas Milne, writing last night in The Guardian, also said he’s not taken in by the Tories’ PR and that Cameron’s “Big Society” push “is a brilliant presentational sleight of hand, which takes their political cross-dressing to new heights.” Underneath this “clever political branding exercise” is “in reality a classic Thatcherite anti-state programme for sweeping privatization.” Parental control of schools, for example, opens the door for “sharp-elbowed” well-off parents to snap up shrinking resources and to privatization for profit through corporate sponsorship. Meanwhile, the Tories’ commitment to offering tax cuts to the richest segment of the population remains unswerving.

Calling the manifesto’s title, “Invitation to join the Government of Britain”, “an obvious absurdity”, Simon Heffer, writing today in The Telegraph, claimed, “It is, in fact, an invitation to read no further.” The well-off Notting Hill set could be expected to seize on the idea of taking over some local institution, “[b]ut what sort of success will this scheme have in the dispossessed mining towns of the West Riding, or around the ghostly mill towns of east Lancashire?”

John Rentoul, writing today in The Independent, claimed that there is an essential fallacy, as well as an inattention to history, that dogs the new Conservative Party: “This was the flying pig manifesto, lighter than air and rhetorically describing a Britain that is never going to be. And the reason we know it is never going to be is because we have been promised it before. The Big Society? It is huge, inflated, fabricated, and mythical. It is about as meaningful as the ‘strong society’ that Tony Blair used to talk about, which is not meaningless, just not real.”

Credibility is at the center of this election – and, ultimately, few seem to believe that the promises made by either the main political parties in their manifestoes will be kept. Or as Heffer wrote, “Since there are so few areas of personal or public life left in which anyone ever keeps a promise, it is hard to see why election manifestos should be taken seriously.”