In the latest episode of Great Lives, Shaun Ley says he likes the "theatre" of politics. This helps explain many of the failings of political reporting.

Mr Ley is not, I suspect, unusual here. When ITV's Paul Brand said that Johnson's "press conferences are 100 times more engaging than Theresa May's", he was praising Johnson's theatrical skills, as was Robert Peston is his fawning report. And a lot of you were unhappy with coverage of last week's G7 conference because it focused upon the theatre of the occasion more than the substance.

Presenting politics as theatre is, however, dangerous and misleading. Ian Leslie gives us one reason. Being an attractive character is good theatre, but it is no guide to whether one is actually competent: Johnson's success is founded largely upon appearing likeable (at least to a particular, influential group) rather than upon any track record of excellence in office. Worse still, we are bad at judging likeability, a fact conmen and psychopaths profit from.

But there's something else. When journalists foreground the theatre of politics they background other important things.

Some of these are facts and interests. Paying attention to the personal chemistry between Johnson and other leaders disguises the fact that there are massive structural barriers to renegotiating the Brexit deal, such as the Irish border trilemma, the EU's desire to maintain the integrity of the single market, and the refusal to renegotiate the backstop.

Other things are long-term emergent developments. Capitalist stagnation and negative real yields should be the key determinants of macroeconomic policy. But these get neglected when journalists focus instead upon the theatre of ad hoc policy announcements, Chancellor's intentions and their relations with Number 10.

Yet other things are basic ground truths. Fiscal austerity has cost every household thousands of pounds, caused thousands of deaths, driven the most vulnerable to despair and suicide, weakened important institutions and given us Brexit with all its costs. And yet many of its architects and supporters have retained their "credibility" with the media, because they've played the theatre well.

There is, of course, a class aspect here. Just as Shakespeare is usually performed with plummy voices rather than in the (to me, more comprehensible) accent Shakespeare used, so the theatre of politics is best done by poshos: would Johnson, Cox or Rees-Mogg sound as "credible" if they had cockney or Scouse accents?

The problem here is not the failings of individual journalists. It is instead inherent in the industry. Journalism values "human interest" stories and the lively anecdote, quote and image - all of which are essential parts of theatre. These, however, impart a systematic bias if we rely too heavily upon them to report political affairs.

Psychologists have identified a widespread mistake people make; we often over-rate character and intentions as explanations for behaviour and underweight external environmental factors, They call it the fundamental attribution error. In treating politics as theatre, the media institutionalises the error.