BBC London and the mayoral campaign
Local politics in the capital, like its national big brother, can be a tough old business. Nowhere does this apply more than in the political rough and tumble around the London Mayor and the city's assembly. To add to the mix, the two mayors to win so far are politicians with a strong national profile in their respective parties, and a sometimes tricky relationship with their respective leaders.
In these circumstances it is the job of the BBC to analyse as impartially as possible what is going on - and that can ruffle feathers.
The Guardian on Monday carried a story about how Guto Harri, the recently departed director of communications for Boris Johnson, tried to influence the screening of an interview on the Politics Show with the Mayor's biographer Sonia Purnell.
It is part and parcel of any political campaigning that the BBC comes under pressure from one side or another about their treatment, and Mr Harri's intervention was by no means unusual. It's pressure we resisted robustly at the time.
BBC London is not alone in focussing on the details of London politics, but we do have a responsibility to try to get it right. Boris Johnson is a larger than life character who is viewed by some of the papers, and some in his party, as a potential leader-in-waiting. He attracts acres of coverage in the national media, little of which concerns the detail of his day job. This means that BBC London sometimes finds that it is asking uncomfortable questions that go into a level of detail that the mayor and his advisers, like many other politicians, may find inconvenient.
It was one such question - a perfectly legitimate inquiry about the approach Mr Johnson took to commercial sponsorship - which caused the mayor to use the F-word on air about our political editor Tim Donovan.
Donovan was asking the question not because he had a hidden political agenda but because he rightly believed it was a matter of genuine public interest. The commercial deal in question happened to involve News International at a time when that that company's activities were coming under increasing police scrutiny. The mayor has to ride many horses: as well as batting for the city, he is charged with holding the Metropolitan Police to account.
Equally, Ms Purnell's biography raised some pertinent points about the mayor's style and when it was published last October it was reasonable to offer her an interview on the regional section of the Politics Show.
But it is ridiculous to suggest that BBC London takes a view one way or the other about which politician holds the mayoralty. We asked tough questions of Ken Livingstone during his term in office, many of which he didn't like either. That does not mean it was wrong to ask them. As you would expect of a political editor, Donovan broke a number of stories (including the existence of Ken Livingstone's three additional children, and allegations of corruption against one of his aides) that the Livingstone team would have preferred did not see the light of day.
Our audience research suggests that the BBC is the most trusted of all sources news and that trust - which we value above all else - is born from being independent, impartial and accurate.
The BBC is owned by all its viewers, listeners and online readers. Their opinions cover the whole political spectrum and BBC News has a duty to pose the questions they want answering. Politicians are passionate and for the most part honest public servants.
But those who represent political parties have, almost by definition, the most committed point of view, and it is they who tend to shout loudest when confronted with the reality of impartiality.
Mike Macfarlane is head of BBC London.