In politics some rows gain potency from blowing up at a bad time. Some because of their symbolic power. Some because of a single memorable televised gaffe that can be constantly replayed. And some because they involve very serious lapses.

It is rare for a single story to encompass all of these damaging dimensions but that is the case with the furore over the Christmas Party at Downing Street last year.

Veteran Tory Sir Roger Gale was probably not trying to be helpful when he told the BBC this morning that the matter had the ‘potential to become another Barnard Castle’. Yet if that is all it becomes then people around the Prime Minister will surely breathe a huge sigh of relief.

Because Barnard Castle, or ‘Domgate’, involved one official bending the rules to protect his family. It resulted in a drop in the Tory poll lead that was very short-lived. And it registered far more intensely among the political and media class and middle class Remainer types who already hated the Government than it did across wider society.

Partygate, by contrast, involves a whole collection of Downing Street officials just wanting to have fun behind the backs of the voters at the same time as they were cancelling the Christmas plans of the entire nation. It relates directly to the dominant political issue of the past two years – the impact of the Covid pandemic on normal life.

It comes hard on the heels of a series of other rows that have appeared to show Boris Johnson being softer on his own elite connections than on the British public, most notably his ludicrous attempt to get Owen Paterson off the hook of a damning standards committee verdict. The opposition’s charge that ‘it’s one rule for them and another for everyone else’ is the kind of dividing line that no prime minister should want to see carved in stone.

The row has exploded too after several months that have seen the PM doing things that are anathema to much of his natural support base: going gaga over green policy, putting up taxes, soft-pedalling on ‘culture war’ issues, raising foreign aid spending again and signally failing to get a grip on the Channel migrant shambles to name just a few.

During his chaotic US presidency, Donald Trump was sustained in many moments of crisis by the fact that he never ratted on his own base. Redneck America knew he was their guy and saw attacks on him as attacks on them. By contrast, millions of 2019 Tory voters have lately been asking themselves whether Johnson might just be another pointless Etonian dilettante. They could be forgiven for thinking as much as they have watched him uselessly trying to woo people who will never vote for him and elites who will never forgive him for Brexit.

It is very harsh on his briefly installed but never unleashed press secretary Allegra Stratton that video of her joshing around with No. 10 chums during a rehearsal for the launch of aborted televised briefings has emerged. But, as Matt Hancock could have told her, in the viper’s nest of Westminster the stuff that looks worst is the stuff that gets leaked.

‘I went home,’ giggled Stratton when asked about this ‘fictional’ No. 10 party which was ‘not socially distanced’. The knowing nods and winks between these elite insiders will surely infuriate voters who had earnestly and in good faith pulled the plug on their own planned gatherings for the good of the country. Johnson’s own dissembling when asked about this party at PMQs last week is now blowing up in his face and also in the faces of all the ministers sent out onto the airwaves in the interim to try and hold yet another unsustainable No. 10 line.

Perhaps that’s why they aren’t going out today to face short-pitched stuff from the media on the PM’s behalf. England’s batsmen may have lost their wickets very quickly on day one of the Ashes series, but at least they padded-up and left the pavilion. Johnson’s dressing room is, by contrast, now full of unconscientious objectors.

Coming at a terrible time, highlighting hypocrisy in a memorable and relatable way, replete with infuriating TV footage and pertaining to the biggest issue of the day, this one has got the lot.

The truth is that the two most important political fundamentals – on the economy and the current Covid situation – are not too bad for the Government. If the Tories fail to hold their hitherto safe seat of North Shropshire in the by-election next week then many will think it is not the party that is in freefall, but its leader.