This is important because the BBC is widely seen as an impartial source of information which has not been captured by corporate interests. But its lack of candour about its contributors makes this an unsafe assumption.

Almost every day, BBC news and current affairs programmes give airtime to organisations that call themselves “think tanks”, but which refuse to reveal their financial interests.

People representing the think tanks often speak on issues of great interest to corporations, without declaring whether or not they are being paid by them. A recent example is an interview on the Today programme with Mark Littlewood, director of the Institute of Economic Affairs, about the plain packaging of cigarettes. Neither Today nor Littlewood revealed that the institute has been taking money for many years from British American Tobacco, Philip Morris and Japan Tobacco International.

In response to complaints, the BBC has refused to accept that it should reveal the relevant interests of its contributors, even though its failure to do so breaches its own editorial guidelines. It seems to believe that listeners should not be told that someone arguing against the tougher regulation of tobacco sales is funded by the tobacco industry. It allows people who appear to act as corporate lobbyists to pose as independent pundits.

While we believe that anyone who is honest about their interests should be allowed to speak, we call on the BBC not to give airtime on controversial issues to organisations which refuse to say who funds them. The financial interests of any contributors in the issue under discussion should be disclosed, and mentioned when they are introduced.