LONDON (Reuters) - Mark Thompson is to step down as the director general of the BBC after eight years in which he overcame battered morale, assaults from Rupert Murdoch's media empire and threats to the corporation's funding at a time of national austerity.
The most powerful television executive in Britain said on Monday he would quit as the head of 17,000 staff after the London Olympics, bringing an end to a tenure marked by huge challenges both from commercial rivals and technological change.
"We have weathered a series of lively storms and been through some trying as well as some very successful times together," he said in an email to staff.
"Rather amazingly, with nearly eight years in the job I am already the longest-serving director general since the 1970s," he said, underlining the difficulty of staying in a job that is the target of frequent attacks from rivals and politicians.
Thompson took over the top job in 2004 as the corporation hit rock bottom following a very public spat with the government over its coverage of the build up to the Iraq war.
With staff staging spontaneous walk-outs in disgust at criticism of its editorial standards, Thompson steadied the corporation and slowly rebuilt trust with the public and government.
"He's been an outstanding success," Claire Enders of consultants Enders Analysis told Reuters.
"The one thing most people did not foresee was that the explosion in digital technology would result in the BBC's having an extraordinary reach and value and its news services being consumed as never before."
That expansion, however, has drawn criticism from rivals.
With eight national TV channels, 50 radio stations and an extensive website, the BBC's size and resources have long attracted envy and criticism led by rivals including James Murdoch, first in his role as chief executive of pay-TV group BSkyB and then as chairman.
As the recession gathered steam in 2008, that criticism intensified as advertising-funded groups like ITV struggled to cope, cutting staff and budgets.
Critics, and the public who fund the broadcaster through a licence tax, were incensed as the corporation lured executives and on-screen talent with huge salaries, and it also drew fire when its commercial arm bought the Lonely Planet travel guides.
However, due to two factors largely beyond his control, Thompson managed to respond and regain the upper hand.
First, the explosion of a phone hacking scandal at a Rupert Murdoch tabloid silenced both Rupert and his son James when it came to attacking the BBC, as they both had to concentrate on resolving the issues at their own company.
Secondly, the settlement of the latest BBC budget was forced down by the government's overall austerity drive.
Last year the BBC agreed to freeze the annual licence fee, payable by every TV-owning British household, at 145.50 pounds, while it also took on extra costs from the government including funding the BBC World Service, which is broadcast overseas.
The agreement was hammered out in a matter of days, stripping out the months of often public negotiation normally involved in setting a licence fee, as the coalition government scrambled to cut spending after taking power.
Unions, staff and analysts felt initially that Thompson had been outmanoeuvred by the government, but many now realise that by agreeing such an early deal the corporation avoided the battleground of public spending cuts.
Thompson said in October that the BBC would have to cut by over 10 percent its staff in management, programming and news divisions.
The BBC's other major achievement during Thompson's tenure was its development of new technologies such as the hugely popular iPlayer, which enables viewers to catch up on missed programmes for free online.
Thompson acknowledged that it had not always been easy.
"I've always been on the side of change because I believe that, in the middle of a media revolution, change is the only way of safeguarding what is so precious about the BBC," he said.
Analysts believe there are no clear candidates for the job, but his departure could open up the way for the first female director general, with both BBC chief operating officer Caroline Thomson and head of news Helen Boaden seen as leading internal candidates.
Reporting by Kate Holton, editing by William Hardy