Why is the simmering batch of election fraud accusations against the Conservatives 2015 campaign team not making more of an impact in the mainstream media? It’s a good question and conspiracy theorists everywhere have already come up with their default answer. It’s a plot.

With an eye-catching fresh allegation around on Wednesday – it’s untested but has caught my attention – all this may be about to change. No, I don’t mean the coroner’s suicide verdict on the young Tory activist Elliott Johnson, though that would be a wholesome development too.

Part of my theory as to why coverage has been low-key is that when one media outlet is making much of the running – Channel 4 News and Mike Crick this time, plus the Mirror – other mainstream media are reluctant to take up a rival’s campaign or seek to rubbish it. We’ve seen that at the Guardian over issues such as phone hacking and Edward Snowden’s revelations about data mining surveillance. It’s common enough, as journalists know. At least the Tory election story has been picked up by the system, as Private Eye’s paedophile stories were not in the 90s.

There’s another obvious explanation this spring. There’s been a lot of news about and even sophisticated and well-funded newspapers, radio and TV companies (they’re all under the financial cosh) can only handle one or two big stories at a time. Tax fraud, terrorist attacks, immigration and people smuggling, the rise of Trump, and of course Britain’s own Brexit debate, it’s been pretty lively.

Here’s C4’s latest update from its website. Here’s a very fair Guardian summary of the story so far and why media treat it warily: fear of libel. Plus a recent update.

As you can see (and may already have known), the allegations – now being investigated by dozens of overstretched police forces – centre around that boring but important discipline, accountancy. The Tories are fighting it.

Should those battlebuses full of eager party “volunteers” sent to key marginal seats the Tories needed to win for that slender 5 May majority have been charged (their hotel bills too) to the constituency’s election expenses tally rather than to the national campaign, as they were in 2015?

That’s pretty serious.Investigations could lead to prosecutions and possibly byelections. The Tories could lose their majority. What a turn-up in a turbulent world.

Tory HQ insists that the volunteers’ expenses were part of the wider national campaign so all is well, though David Cameron is – too late – starting to send out uneasy vibes, see his Robert Peston interview on ITV. I stress that the police, who have been given extra time by the Electoral Commission, are only at the investigation stage with no charges laid, let alone proved.

Wednesday’s instalment, billed as an exclusive by the Canary news website, opens up what looks like a significant new front, by claiming that people acting for the party also broke election law in regard to the private polling they are allowed to do during campaigns within strict limits about how they do them.

What’s at issue here is known as “push polling,” the US Republican-pioneered technique whereby you seek to influence the result of a poll by the way you frame the question. “Do you favour Britain leaving the EU to become a proud, sovereign state again instead of a puny province of Europe run by crooks and toadies?” would be one example of the genre.

I emphasise that I can’t vouch for what Canary’s whistleblower is saying here – he’s said to be a man who worked on the highly targeted polling and says it breached guidelines – but it looks a solid piece of work, worthy of examination and explanation.

Whether or not the cost of the disputed work was all declared on the party’s overall election expenses is a further sub-plot which just may be above a young whistleblower’s pay grade. But what his bosses told him to say probably isn’t.

Ex-Tory Ukipper Mark Reckless, now a Welsh assembly member, made similar claims after he was defeated in Rochester last May. The Canary investigation has dug into assorted expense claims and activities in several such seats crucial to Cameron’s success.

It’s worth noting in passing that polling firms linked to Jim Messina, the American political consultant who worked for Obama but was hired by Cameron, are in the frame here. That too may or may not prove significant. His former colleague, the more idealistic David Axelrod, who did a bit of work for Ed Miliband, calls Messina a hired gun.

On the radio silence dimension, the New Statesman set out a reasonable explanation here as to why this has not been bigger news. It has been reported and the Daily Mail is periodically on the case in its savage way. It doesn’t like Lord Feldman, Dave’s Oxford and tennis pal who is also party chairman. Nor does the Mirror.

I would add two modest further points of explanation. One is that political parties nowadays are run from the centre as permanent campaigns, poll-driven and slick. Most of those in charge are young and relative newcomers, not the old sweats of legend in all parties who knew the rules inside out, what you could get away with or not.

So Cameron’s crew may be calculating rascals. They may also prove to be more hapless innocents. We’ll find out, though no sensible police force will rush to overturn an election result. Playing politics has already cost the Police Federation, the coppers’ union, much grief.

There’s another possible explanation. Jeremy Corbyn is famously not keen to play the man rather than the ball. This is admirable and evident at PMQs where Flashman Dave plays both at once when he kicks Labour’s man in the balls.

Russia Today (RT) is understandably keen on the story, retaliation for the unkind things we say about the Putin way of winning. So if Corbyn doesn’t make a fuss and leaves it to the SNP, Mike Crick and Russia Today, who will take up the charge?

Ed Miliband perhaps, it was his election defeat after all so it should be personal. It might even provide a welcome respite from Brexit madness.