“Fool, or knave?” That is the question hanging over Tom Watson as the police inquiry into the outrageously botched ‘VIP abuse’ investigation puts his conduct back in the headlines.

Although the officers and detectives at the heart of Operation Midland have been formally cleared of actual misconduct – sometimes without even being interviewed by the watchdog – a separate inquiry has reportedly found no fewer than 43 separate failings by the Metropolitan Police.

Watson himself is now facing renewed calls to quit from individuals, including ex-Tory MP Harvey Proctor, who fell victim to the false accusations of Carl Beech, who spun a fantastical conspiracy theory about a Westminster paedophile ring as informant ‘Nick’.

Not only did the West Midlands MP encourage Beech to report his allegations to the police, he also used his position in the House of Commons to amplify them. In 2012, he went so far as to say that there was “clear intelligence suggesting a powerful paedophile network linked to parliament and No 10”.

With ‘Nick’ now exposed as a serial fantasist and facing almost two decades in prison, two explanations for Watson’s conduct present themselves.

The ‘fool’ option is not just that this supposedly savvy politician fell for Beech hook, line, and sinker. Whilst that is a remarkable failure of judgement, Labour’s now-Deputy Leader went considerably further when he decided to use his influence and profile as an MP to lead what can fairly be described as an extremely aggressive witch hunt, prejudging the evidence (had any emerged) and preempting the proper course of justice.

Alternatively we have the ‘knave’ scenario, in which Watson suspected that Beech’s claims were at the very least heavily embellished but, emboldened by his successful campaign against the News of the World, pressed a perceived advantage anyway. This certainly seems to have been the case for at least one of his confederates, one of whom was reported in 2015 as saying there were “well up for a witch hunt against rightwing Tories.”

We’re unlikely to ever find out which scenario is the true one – and in one sense, it doesn’t really matter. When you have police officers going on the record to a Commons committee that Watson’s interference in their investigations prevented them from doing their jobs, and the man himself admitting that he went public with Leon Brittan’s name before even informing the authorities, that raises questions about conduct that not even the purest motives could excuse.

For all that, at present it seems unlikely that Watson will face the direct and immediate consequences that ought to follow from a Labour Party prepared to endure the spread of antisemitism under Jeremy Corbyn or keep John Bercow in post in the face of a damning bullying inquiry because Brexit, in Margaret Beckett’s words, “trumps bad behaviour”. My suggestion in 2015 that Watson might be on his last legs now looks very naive.

But that doesn’t mean this couldn’t have serious, perhaps terminal implications for his career. The scandal has undermined the Deputy Leader of the Labour Party only weeks after the Corbynites tried to abolish his position altogether. It is a serious strike against his moral authority, a precious resource when it comes to holding the Labour leadership to account over antisemitism. Even if he survives, his capacity to resist the Far Left may be further reduced.

On top of that, the Sun on Sunday reports that the Conservatives have now launched a concerted campaign to target Watson’s seat of West Bromwich East at any imminent general election. Although his majority of over 7,000 would normally be safe, CCHQ reportedly think that a combination of factors could bring him down: the constituency’s heavy Leave vote; the scandal of Watson’s personal conduct; and the fact that neither the official leadership nor Momentum will have much interest in throwing resources at saving him.

Fool, or knave? If the perfect storm foreseen by Tory strategists does come to pass, it may not ultimately matter. As Yeats put it: “The Light of Lights looks always on the motive, not the deed; the Shadow of Shadows on the deed alone.”

We cannot speak for the Light of Lights. But perhaps, at last, the shadows are drawing in on Watson’s time in politics.