The head of the BBC made an impassioned defence of the state broadcaster on Friday, following years of mounting criticism from rivals and politicians accusing it of being too large and too arrogant.

Mark Thompson used the industry event MacTaggart lecture to respond to James Murdoch, the heir apparent of News Corp, who used the occasion last year to lambast the BBC for having a chilling ambition that damaged its rivals.

Director General Thompson, who noted that Murdoch had also turned his ire on that other sinister force the British Library, said the corporation was much loved by the British public, and even by those who read Murdoch's newspapers.

He said he accepted that the broadcaster needed to reduce in size as the country adapts to tougher economic conditions, but said a cut in the licence fee paid by the public to fund the corporation would damage the British creative economy.

Support for the licence fee is as high, if not higher, today than it was ... in the 1980s, he said. Then there were four channels. Now there are hundreds.

The purists have spent a generation making the free market case for abolishing the licence fee and the British public agrees with them less now than they did when they started.

The BBC, which is known around the world for its news, drama and factual programming, has been criticised in recent years by much of the British press and politicians for paying its executive staff and top talent excessively.

Its size, across TV, radio and online, has also been called out of proportion compared with commercial rivals who have been hit by the downturn in advertising.

Thompson said these issues were being used in Britain against the corporation in the same way that commercial and political forces were undermining the independence of public broadcasters in other European countries, such as Italy and France.

In the UK, they know that a frontal assault will fail so they adopt different tactics, he said. Exaggerated claims about waste and inefficiency. Nit-picking about the detailed mechanisms of governance and accountability.

He also pointed out that Murdoch's pay-TV firm BSkyB was already Britain's biggest broadcaster by far in terms of revenues and produced strong competition for all media groups.

A year ago, James Murdoch fretted aloud about the lamentable dominance of the BBC, he said. He was able to do that only by leaving Sky out of the equation altogether.

He said, however, that Sky had failed to invest enough in British content and had chosen instead to spend its millions on the rights to live sports and movies.

(Reporting by Kate Holton; Editing by Gary Hill)