DG Tony Hall says ...  

"there has been a "major change" over the past 20 years which has made the foundations of the BBC's independence "weaker". The government has yet to comment.
"When I was working in news and current affairs in the '90s, the independence of the BBC was protected by a set of quiet customs and traditions," he will say.
"Back then it was Willie Whitelaw who'd provided us with the certainty of a 15-year Charter, underpinning our independence by allowing us stability through the political cycle.
"When I returned to the BBC as director general, I was struck by a major change. The foundations of the BBC's independence had become weaker. The traditions and informal arrangements which protected it had been eroded."

Source BBC news, here.

The speech is quoted here, in "The Independent".