Lib Dem justice minister Lord McNally says today that debate about fundamental rights in the EU must be based on ‘an objective and evidence-based analysis of the facts’. The MoJ is even seeking ‘evidence’ from lawyers. How gratifying.

Earlier, his lordship was to be found on Radio 4’s Today programme talking about family mediation. His performance there, tetchy and faltering, demonstrated a somewhat less overt commitment to empirical policy-making.

The number of couples attending out-of-court sessions to resolve family disputes since cuts to legal aid were introduced in April has plummeted by 47%. Eminent divorce lawyer Marilyn Stowe had been on the programme to point out the dangers of people going unrepresented.

Ah, yes, said McNally, but Stowe’s views don’t count – ‘the clue’s in the name’, he said. As a solicitor who is paid to represent clients, she has a producer interest. Ergo, her ‘evidence’ is inadmissible.

The interviewer tried a different tack. Had money not been an issue, would the government have cut family legal aid?

But money was an issue!, McNally declared triumphantly, as if this somehow answered the question.

As I groaned audibly over the cornflakes, Sarah Montague gamely reverted to the statistics. When will one be able to judge from the evidence (that word again) whether government attempts to promote mediation as an alternative to courtroom divorce and custody battles are failing?

Blustering once more – this was ‘typical of the Today programme’, McNally grouched – the minister once again declined to answer.

The evidence (sic) is piling up that we have entered an era of evidence-free policymaking. What matters is not whether a policy will ‘work’, or whether (a real luxury, this) it is just or fair. What matters is how it is immediately perceived by the public and consequently whether it can yield a short-term electoral dividend. Thus, there are votes in smearing legal aid lawyers as fatcats from whom the cream must be summarily withdrawn. Which may be promoting a fiction, but that is missing the point.

Similarly, when home secretary Theresa May announced recently that she was targeting ‘health tourists’ who use the NHS for free, she did could not say how much this actually costs the taxpayer. The Royal College of GPs, which does know, puts it at 0.01% of the health budget (that is, next to nothing).

This trend began under New Labour, Tony Blair being the acknowledged master of populist empathy. Its corollary is the malign portrayal of professionals as vested interests who actually embody the problems that our nobly disinterested politicians are trying to solve. So teachers cannot have legitimate views about how to run schools; doctors are merely swinging the lead when they oppose health service reform; and lawyers can talk to the hand on the subject of running a decent justice system.

Professionals are getting a taste of the medicine prescribed to the trade unions a generation ago. They are the Enemy Within.

It’s an appallingly cynical creed, assuming as it does that professionals are as ruthlessly self-interested as those by whom we are governed. In fact, it negates the very notion of professionalism, which denotes an ethical underpinning to a learned calling. (Though the word is now routinely abused. Calling footballers who are paid to play ‘professionals’ is one such misuse.)

The downgrading of ‘evidence’ is dangerous, too, because a cavalier attitude to the facts damages democracy. As an underreported survey for the Royal Statistical Society recently highlighted, on the facts which inform key social policy issues, the Great British Public is utterly clueless. In their Britain, one in three of us is an immigrant (one in seven, in reality), violent crime (down 20% since 2007) is going up, and one in seven underage girls gets pregnant every year (one in 200).

The role of the true professional is to act as an indispensable bulwark against the power of corporates and the state. When the public are so startlingly ignorant, that role is more important than ever (which is why the government is trashing judicial review, incidentally).

Prejudices crowd out rational thought, of course, but our politicians seem to believe this is infinitely to be preferred.  After all, if (as ex-Treasury secretary Liam Byrne told his successor David Laws) ‘there’s no money left’, there are no rational choices to be made anyway. Except one. Carry on cutting.