BBC Trust Chairman Lord Patten Steps Down
Lord Patten has stepped down as BBC Trust chairman on health grounds after undergoing major heart surgery.
Chris Patten announced that he was leaving with immediate effect "on the advice of my doctors."
He said: "I have concluded that I cannot continue to work at the same full pace as I have done to date, and that I should reduce the range of roles I undertake.
"On this basis I have decided with great regret to step down from much the most demanding of my roles - that of Chairman of the BBC Trust."
The BBC said Vice Chairman Diane Coyle will take over as Acting Chairman until a successor is appointed.
Lord Patten had been head of the BBC Trust since May 2011, a period which has seen the organisation go through three director-generals and weather a number of high-profile scandals.
The organisation has come under fire in recent years over excessive executive pay, its Diamond Jubilee coverage, and revelations relating to a number of former BBC employees, including Jimmy Savile.
He was among a number of BBC bosses called to give evidence before a Commons Public Accounts Committee over what they knew about golden goodbyes which saw senior executives leave with thousands of pounds more than their contracts demanded.
Former Director General Mark Thompson subsequently accused Lord Patten and trustee Anthony Fry of "fundamentally misleading" committee members about the extent of the Trust's knowledge and involvement, something the BBC Trust chairman strenuously denied.
His term was due to run until the end of April 2015.
Lord Patten was admitted to hospital on April 27 after experiencing serious chest pains. He said he was treated with a combination of bypass surgery and angioplasty which had left no permanent damage to his heart, but had hindered his ability to fulfil the obligations of the role.
He said: "This is a position that requires and has received from me 100% commitment, and has been my priority at all times.
"It would not be fair to my family to continue as before; and equally it would not be fair to the BBC and those it serves not to be able to give that commitment which the role demands."
Alongside his chairmanship Lord Patten also serves as Chancellor of Oxford University and sits on a number of advisory boards.
Prior to joining the BBC he had held several ministerial posts in the Conservative Party during the 1980s and was party chairman from 1990-1992. He was also the last governor of Hong Kong.
Commenting on his departure, current BBC Director-General Tony Hall said: "I have enjoyed working with Chris over the last year; he is a staunch believer in the BBC and he has brought his vast experience to the role of Chairman of the BBC Trust.
"He has steered the BBC through some of its most difficult days."