BBC chairman Michael Grade is resigning to become executive chairman of Britain's largest commercial broadcaster ITV PLC.
Grade's defection comes at an awkward moment for the BBC, which is hoping to win an above-inflation increase in the annual license fee paid by every home with television.
ITV said Grade would assume his post sometime next year.
Grade's salary was not disclosed, but the Guardian newspaper said he was likely to be paid more than the £1.8 million (US$3.5 million) earned by former chief executive Charles Allen last year. Grade was due to be paid £140,000 (US$271,000) a year as head of the new BBC Trust, the post he was due to take at the state-owned broadcaster.
ITV acknowledged that the appointment breaks the guidelines of Combined Code for UK companies, which recommends keeping the roles of chairman and chief executive separate.
In August, ITV said revenues at ITV1 -- its main channel and largest earner -- fell 8 percent to £654 million in the first six months of the year.
Last week ITV rejected a £4.7 billion takeover offer from cable operator NTL Inc.
Anthony Salz, vice-chairman of the BBC Board of Governors, said the corporation was disappointed by Grade's decision.
"Michael Grade has been an inspirational leader of the BBC since his appointment in May 2004," Salz said. "His passion for quality and value for money has been a driving influence for major changes, all with the sole purpose of delivering a better service for the public."