BBC One's Breakfast with Frost is to finish at the end of May

Sir David, who has been one of the UK's leading interviewers for more than 35 years, told Broadcast magazine an aggressive style was "a disservice".

"In general, there is more of the hostile, aggro-questioning than there was," he said. "But it's not always remotely productive."

He said the trick was "to get people to open up, not shut up".

'Testing quality'

"If you can relax someone but still ask testing questions, then you can get much further," he told the UK media magazine.

"It's all about the testing quality and the intellect of the question, not the style," he added, but refused to name names.

Sir David is retiring from BBC One's Breakfast with Frost on 29 May - the 500th show. His new programme, The Frost Interview, will start later in the year.

He has questioned leaders and celebrities since the 1960s, including a famous interview with former US President Richard Nixon who admitted for the first time he had let his country down over the Watergate affair.