Dominic Raab was widely mocked for his remarks about only recently understanding the importance of the Dover-Calais crossing (I defy anyone not to laugh at this from Artist Taxi Driver). The derision may be a little over the top, as it was when Gove was misquoted as having had enough of experts, but they and more serious admissions of ignorance are ridiculed because they reveal a deeper truth. As in the US, those ruling us in the UK do not really know what they are doing to a much greater extent than in previous years (see George Eaton here).
That last sentence perhaps requires clarification. They are not fools without any purpose. Brexit is a triumph of the heart over the head. They know what they want, and just do not care too much about the damage it will do. But the ‘misunderstanding’ by Brexiters over what they signed up to in December 2017 that persisted for weeks shows how dangerous not paying much attention to facts (in this case the words of an agreement) can be. Theresa May wasted at least a year completely misunderstanding the EU, and firing those in government that did. Perhaps her biggest act of ignoring the obvious was embarking on the Article 50 process without any prior discussion of what was possible and what was not, which as many people noted at the time was a sure way of ensuring the EU got pretty well what it wanted. If you do not believe all this, read Chris Grey here.
If you are tempted to put this all down to the unique stupidity of Brexit, or the uniqueness of Donald Trump, you really need to read my new book (short summary here). These traits were there with austerity, or the ‘hostile environment’, if you did the research. Economic historians of the future will discuss at length which did more needless economic harm to the UK economy, austerity or Brexit (assuming Brexit goes ahead). The only real debate about George Osborne, who committed the UK to pro-cyclical fiscal policy in the middle of the Global Financial Crisis, was whether this reflected deliberate deception or unforgivable economic ignorance (chapter 1.13 of my book), and if the former whether it was all about shrinking the state or a more superficial search for political advantage. In later years it became simple deficit deceit for neoliberal ends. In the US the priority of the Republican party for years has been tax cuts for the rich paid for by reducing state services for the poor, and a selective concern for the deficit combined with imagining tax cuts pay for themselves have been useful devices (lies) to achieve that. .
If politicians on the right display wilful ignorance to achieve their goals, they have knowledge of a kind that exceeds their opponents on the left by miles. They are extremely well versed in the arts of political spin, or more generally of getting votes by disguising the true objectives of their policies. Part of this works through think tanks, and part through the right wing press. In turn both these groups, plus politicians themselves, put huge pressure on the media (in the UK the BBC in particular), and that pressure works. The table below comes from this study and shows how often the BBC used political sources in 2007 and 2012:
Whereas the bias towards Labour was small in 2007, and was perhaps expected as they were also the government, by 2012 Conservative sources were almost double Labour sources. (Ironically LibDem sources declined in 2012, despite being in government.) Something similar happened to think tanks, according to this study comparing 2009 and 2015. For example in 2015 the IEA was referenced about 3 times more often than the IPPR. The detail in the paper of where the right wing bias was most prevalent is noteworthy although not that surprising.
Even when the BBC does manage to maintain balance, as it did in the 2016 referendum, this is often at the expense of facts and expertise. (Much the same occurred in the US before Trump was elected, as I recount in Chapter 7.8 of my book.) This leads to an obvious danger which we can see the political right exploiting more and more in both the US and UK. Whereas spin used to involve distorting the truth by selective use of facts or inventing clever but misleading slogans, it can now involve simple lying, as I experienced with my own work recently. Has this really got worse over time? I cannot cite any hard evidence for the UK, but there does seem to be that impression (see the first few tweets of this thread and this article by Stephen Bush). In the US there can be no doubt things have changed: not just Trump but with much of the Republican party over issues like health care or climate change.
This emphasis on the right of getting people to vote for you at the expense of examining the impact of your policies is reflected in the careers of many of the Brexiters, as William Davies points out. Trump was a TV star before he became President. Reagan was a movie star, although he at least was a Governor before becoming President. It is hard not to see these trends in right wing politics as starting with Reagan and Thatcher, and that much abused term neoliberalism. It was Thatcher that really began the politicisation of and disdain of the civil service, when being ‘one of us’ was valued over expertise.
You do not need experts, or you are only interested in experts who are one of us, because you have an ideology to guide you to the truth, or you are suspicious of any expertise that does not share your ideology. One of us is one who shares an ideology, in this case the ideology of neoliberalism. Neoliberalism wants as much as possible to be organised as a market. If that includes democracy itself (democracy is just a market for votes) then there is nothing preventing you employing all the tricks of advertising, preferably not encumbered by any regulators. Politics becomes the art of selling, rather than the assessment of policy. 
Why do I call the period after 2010 in the US and UK neoliberal overreach, as opposed to straight neoliberalism in the 1980s? After all there are some similarities in the UK between the two periods. Both Osborne and Thatcher started their terms in government with economic experiments that went against received economic wisdom. Both tried austerity (a fiscal contraction in a recession). I don’t want to minimise the harm Thatcher did to parts of the country, but her austerity was temporary  and the monetarist experiment was quickly abandoned, with the result that the recovery was only delayed by a year or two and the economy in aggregate eventually recovered in the true sense of the term. In contrast the slow recovery in the UK, US and Europe since 2010 seems to have had permanent and large negative effects. An interesting question is how much this difference between the two periods in the UK reflects different degrees of control over the media.
But the main reason I call what happened after 2010 overreach is that the neoliberalism of both Reagan and Thatcher was in many ways popular, and so there was less need to dress policies up as something they were not. In 2010 there was no popular demand for a reduction in the size of the state, so it required a form of subterfuge: what I call deficit deceit. Tight targets for immigration made no sense for neoliberals who wanted to reduce red tape for firms, but it was useful as a way to deflect anger over austerity and win votes.
A better way to describe Brexit than heart over head is the triumph of ideology over knowledge. Neoliberalism isn’t the only ideology behind Brexit. There are elements of English nationalism that William Davies discusses in his piece noted above and Anthony Barnett discusses so well in the Lure of Greatness. But the disinterest in facts or experts and the absence of shame in telling whatever lie is required to get what they want is very much part of what I call neoliberal overreach. To those to whom evidence based policy is natural they appear fools, but they know exactly what they are doing and in terms of deception they are rather good at it.
 In this particular sense Labour from the 1990s to 2015 were not at all neoliberal. For example contrast Labour's 2003 Five Test analysis with the current government's lack of interest in the analysis of different types of Brexit. The glaring exception was Iraq, and that reflects what happens when you erroneously believe the national interest is to follow neoliberals in the US.
 Fiscal policy was tightened from 1980 to 1982, but this was almost completely reversed by 1984. In contrast fiscal policy was tightened in 2010 and it continued to be tightened until the present day.