BBC One must broadcast at least 40 hours of peak-time current affairs programmes a year under new regulations brought in after an internal review found that the channel's coverage lacked "impact".
The changes, introduced by the BBC Trust, state that the channel has to offer analysis of "issues of national and international concern" alongside "regular political coverage and topical debate".
BBC figures show the channel has broadcast more than 40 hours annually in recent years, with an output of 50 hours last year and 49 the year before.
The trust review, published earlier this year, said the corporation's current affairs shows needed to ''do more to cover stories and issues which stand out''.
It found that audiences rated the rival Channel 4 News more highly for investigative journalism and stated: ''The challenge facing the BBC's Current Affairs is therefore to make greater impact.''
The move to ring-fence its output comes after a troubled few years for flagship shows including Panorama which was criticised after filming undercover during a student trip to North Korea.