The BBC’s inquisitor-in-chief Andrew Neil is enjoying a good election but are the big parties’ big ideas making it too easy for him?

He would not seem an unduly squeamish man but even this senior figure in the financial markets, operating daily in the bloodiest of blood sports, found it a hard watch: “To be honest I found it a bit much. By the end I was looking through my fingers, thinking, ‘Is this really fair?’.”

The banker in question was speaking in the aftermath of Andrew Neil’s prime-time evisceration of Jeremy Corbyn and, while having no sympathy for the Labour leader’s revolutionary socialism, was nevertheless left wincing by Neil’s forensic mercilessness.

I get it. These interviews are 18-rated, slasher-flick spectacles. I worked under Andrew Neil for a number of years, and my terror of his occasionally acerbic tongue was matched only by my appreciation of his journalistic acumen. Having watched Corbyn and Nicola Sturgeon being carved into meaty chunks in recent days, it’s easy to understand Boris Johnson’s reluctance to submit himself to the point of the same bloody sword.

Decency demands he does it, of course, but self-preservation rather than decency has always been Johnson’s preferred modus operandi.

I have a theory about why this election’s round of interviews has been quite so savage – almost too easy for an interrogator of Neil’s calibre. This is that none of the parties is offering a defensible, straightforwardly measurable version of the status quo. None is suggesting the UK trundles along as it is, with a few modest tweaks here and some light trimming there.

Quite often a sitting government will go into an election with the message “don’t let the other lot in to blow it”. Similarly, the opposition will regularly present itself as the team to restore sanity and stability to the nation’s affairs, the current administration having made such a dreadful mess of things. Not on this occasion – it’s cackling, freewheeling upheaval and dizzying, headlong turbulence every which way.

The Tories have thrown off the stabilisers and are racing us into the debatable territory of Brexitland; Corbyn’s Labour is proposing a vast programme of nationalisation, huge increases in public spending, and a major restructuring of foreign policy; Sturgeon is set on securing a second independence referendum by next year, with a Yes vote opening up all sorts of sticky challenges; even the boring old Lib Dems have cast democratic norms to the wind and are promising to revoke Brexit without asking, if they win a majority on December 12 (don’t laugh).

This war-cry politics, this setting course for unmapped territory, produces pledges and predictions that are often on the heroic side and that are, inevitably, heavily reliant on guesswork.

There isn’t much robust science behind the speculative data that is produced. In some cases, the politicians are literally making stuff up – this is election propaganda, not something to meet the standards of the Audit Commission. The economic consequences of the UK becoming a socialist state, of Brexit and of Scottish independence are all unclear, possibly severely disruptive, and at least highly contestable.

Neil approaches all this like a one-man wolfpack circling a herd of tottering lambs. But, unlike the wildlife documentaries, the camera doesn’t move off as the killing commences. Your tax plans will cost how much? You’re going to find money for the Waspi women how exactly? You’ll manage Scotland’s currency transition on what timescale? Wince away, my banker friend, wince away.

Many MPs and ministers grumble and groan about having to face this kind of aggressive media probing but, in truth, it is they who are being done a favour.

The smarter politicians understand this – a senior Cabinet minister from the New Labour era told me this week that he had always quite enjoyed sitting down with Andrew Neil.

“If you knew your stuff you were usually OK. Like Andrew, I was a details man, I knew my numbers as well as he knew my numbers, and so I did all right.”

Combative, sceptical journalism matters in this dreamy-eyed, ultra-ideological, experimental era of politics. When leaders are putting the tribal fantasies of their members above the more humdrum desires of the electorate – whether Brexit or socialism or independence – an inquisitive media performs a quasi-constitutional role as a check and balance.

If politicians are to demand democratic majorities for these potentially transformative but hugely risky steps their ambitions should first be tested to destruction, the bits shonkily held together with gaffer tape given a good thump, the spotlight shone in their face: do you know what you are doing? Prove it.

This isn’t to say the above ideas are bad ones – we’ll all have our own preferences. And it’s clear that the failure of one totemic British institution after another in recent decades, along with the financial crash, the rise of technology and the coming to power of populists around the world, challenges us to think differently about future opportunities and challenges.

The environmental and economic idealism of the youthful New Left should be, and often is, inspiring. They are reacting against a capitalist system that seems to create too-great inequalities and that has opened up intergenerational disputes.

Their proposed solutions may or may not be overly extreme and even counter-productive, but their campaigning verve is at least forcing mainstream Establishment powers to reconsider the nature of their own policies.

Many of us find Brexit a hard pill to swallow but, when we examine the reasons behind the 2016 referendum decision to leave, we are able to understand that too many communities have felt left out of the modern, globalised world.

This needs to be addressed, whether Brexit or no.

Similarly, the tortured British politics of the past few years has made it easier for some of us who voted No to independence in 2014 to understand why so many voted Yes, feeling as they did that Scotland’s voice was not being heard and that it was time to “take back control”.

Ultimately, and despite the abuse received from political activists and social media hangers-on, the media (imperfectly) fulfils its function at moments like this by representing the public. There’s a lot of big talk coming from our current crop of politicians, but just how realistic and feasible are many of these radical policies? Are they affordable? Are they wise? Do Jeremy and Nicola really know what they’re talking about?

So, Boris, why don’t you let that nice Andrew Neil ask you a tough question or two? In the longer term, you might even have reason to thank him.