As well as promising to make "more high-impact memorable programming", the corporation's digital ambitions provide a further threat, particularly now that it has won the digital terrestrial platform with BSkyB.
Tessa Jowell, the culture secretary, is expected to give approval to the digital youth channel BBC3 in the next few weeks. Industry estimates suggest that, depending on which, if any, conditions she places on BBC3, this could cost commercial TV channels between £6 million and £25 million and could put the future of pay-TV channels, such as E4, at risk.
This criticism was echoed in Parliament where Gerald Kaufman, the chairman of the culture, media and sports select committee, condemned the use of licence-payers' money to challenge commercial rivals.
Marshall said: "The BBC is the biggest single threat to advertisers now and for the foreseeable future. There seems to be little control or accountability over the BBC and its latest statement could be interpreted as a further attack on the commercial sector."