Anthony Sethill, ONdigital's commercial director, announced he was leaving the group. Mr Sethill said: "I believe this is the right moment for me to make the move. It will be a wrench to leave but I am proud of what we have achieved."
Mr Sethill, 37, was a senior executive with Amstrad, the computer company owned by Tottenham Hotspur's boss, Alan Sugar, before joining ONdigital a year ago.
The company, jointly owned by the ITV companies Granada and Carlton, declined to comment on whether Mr Sethill had found another job.
An ONdigital spokesman said the company had been told of Mr Sethill's decision to leave "some weeks ago" and had interviewed internal and external candidates before choosing his replacement, Jim Ratcliffe, the managing director of Granada's TV rental shops.
Mr Ratcliffe, a 43-year-old Australian, was a member of the taskforce that prepared ONdigital's licence proposal last year.
ONdigital yesterday denied that the management shake-up would jeopardise the marketing strategy for the new 30-channel digital service due to be launched on 15 November.
The company is planning an advertising blitz before the launch to woo the 17 million households who have still to subscribe to pay TV. ONdigital is fighting a bitter battle with Rupert Murdoch's Sky for the lucrative digital TV market. Sky launched its satellite digital service at the beginning of the month.
Live TV, the cable channel made famous by its Topless Darts and News Bunny features, yesterday announced the closure of its city television stations in Liverpool and Edinburgh.
Its national service will still be available to cable subscribers.
The closures may cost 27 jobs and follows the closure by Associated Newspapers of its local cable service, Channel One, last month.Reuse content