At the same time, the politicians' lack of credibility, already at an 'alarmingly low ebb', enhances the authority of the news programmers, Paul Dickerson, a psychology lecturer at Roehampton Institute of Further Education in south-west London, said.
He told the meeting: 'The high reputation of trustworthiness enjoyed by programmes like the Nine O'Clock News may therefore depend partly on production techniques that systematically undermine the credibility of politicians.'
He added that the 'techniques whilst rendering the news authoritative and accessible serve to undermine the legitimacy of claims made by politicians in general'.
After analysing five lead items on the Nine O'Clock News last May it was clear that the main technique for establishing independence and objectivity was to present several perspectives of the issue under discussion.
Mr Dickerson warned that these were subtle choices on the part of programme-makers and that, unlike newspapers which run leading articles which state their position, the television news programmes suggested that their approach was 'commonsensical' when in fact other choices could have been made. 'The viewer may not be aware of this.'
He said techniques used to establish the programmes' authoritativeness - the use of experts in the studio - tacitly implied that claims made by politicians could not be taken at face value.