Politics is a blood sport – but I fear that some nasty and base elements, outside the established limits of the game – are entering a British general election campaign in a way rarely seen before.

Yesterday, the Observer relaunched with big fanfare – and a big accusation. The prime minister was a bully, claimed its star columnist Andrew Rawnsley, whose new book ‘The End of the Party’ was being serialised in the newspaper. The “evidence” came from “Downing Street sources” – and apparently credible ones. This is not the first time that Gordon Brown’s temperament has been called into question: others have claimed previously that mobile phones and printers get chucked around No 10; he admits himself that he ‘gets angry’ in his pursuit to get things done. But he and his closest advisors, including the ubiquitous Peter Mandelson, denied the “bullying” charge.

Later on Sunday came a new twist: the head of the National Bullying Helpline claimed that Downing Street staff had called her service to complain about the prime minister’s behaviour. Additional credibility? Maybe – but check the source and the motivation. The National Bullying Helpline was set up just a few years ago – it is a charity, but not an long-established one. Its patrons include a Tory MP (Ann Widdecombe) and a Tory councillor. The front page of its website features a quote from David Cameron. Secondly, the essence of a charity helpline would seem to be confidentiality – as pointed out by rival (and longer-established) charity Bullying UK.

There may be no smoke without fire – but the smoke has a distinctly partisan smell. And should the media – especially the BBC – be leading with this type of story (especially the Observer claims item, which essentially amount to a puff-piece for the newspaper)? Other political stories, such as the Tories’ poll numbers dropping below 40%, were nowhere to be seen.

However, a more worrying portent of a vitriolic campaign ahead came via Iain Dale’s Diary, on which the serial Tory selection process failure posted some ‘artwork’ that depicted Gordon Brown as Hitler (as Danny Finkelstein said on his Twitter feed, the demonisation of Gordon Brown is not so worrying as the trivialisation of Hitler). The parallels with recent hyperbolic debate in the United States are obvious, and worrying for the level of debate in this country in an election where there are real differences between the parties on issues of taxation, economics and the welfare state, probably for the first time in about fifteen or twenty years.

So why not have a serious debate about the best way to reach recovery, how we pay for public services, how we run state assets, what our foreign policy should be, how we should produce our energy? With all these challenges, we need ideas, not innuendo.