Parliament can ill afford to lose an MP of Harriet Harman's class
Harriet Harman, a former acting leader of the Labour Party and a staunch and valuable MP on the Opposition benches, is in danger of being dumped by the ultra-hard-Left Momentum campaigning group.
Momentum has seized control of her Camberwell and Peckham Labour constituency party, which bodes ill for Ms Harman, who has held the seat with distinction for more than 30 years.
The left-wingers now have achieved a majority on the executive committee of her south London party, so that her political future could well be in jeopardy.
When she was acting leader, on the resignation of Ed Miliband from the top job, she usually gave as good as she got during the weekly Prime Minister's Questions joust and even occasionally got the better of the blustering David Cameron.
I cannot begin to understand why she did not go for the leadership herself at that time. I think she would have won it.
And I suspect, even now, she still regrets that she did not then throw her hat in the ring.
However, I am sure she will fight hard to save her political skin if, as seems possible, Momentum does start baying for her blood.
The parliamentary Labour Party can ill afford to lose people of her calibre.
Parliament has spoken loud and clear on the historic decision to go ahead with vital Heathrow Airport expansion. And, despite the diplomatic absence of truant Foreign Secretary Boris Johnson on a convenient away-day ticket to Kabul to avoid having to vote, MPs gave a huge majority for the building of a third runway - essential for the UK's economic well-being.
Now - and without delay - the bulldozers should be fired up and a start made on this already long-delayed project. Otherwise, there will be yet more interminable delays as the "antis" serve notice that they are already engaged in talks with legal experts in yet more attempts to scupper this development.
What is more, Jeremy Corbyn's also warned that, if Labour gets into power, he will stop the project, depending on how far advanced the work has progressed at the time.
The Government should contemplate the likelihood that if all the naysayers had been listened to and if every discovery of a colony of rare beetles had been allowed to stand in the way of progress, there might have been no industrial revolution and no national network of motorways.
That is why the Government should regard the huge Commons majority last week in favour of the expansion as the green light, go-ahead for action.
They should roll up their sleeves, defy the antis and get to work straightaway - no ifs, no buts.
Temper! Temper! Environment Secretary Michael Gove, outwardly the mildest of men, was so livid about the Cabinet's divisions over the crucial customs union issue that he actually tore up his papers relating to the subject.
You need go no further than this display of fury to understand the state of disarray and shambles in the Cabinet.
After weeks of dithering and disputation, the saucepan, so to speak, has finally boiled over.
Yet the official Opposition seems incapable of exploiting this deep-seated weakness at the topmost echelons of Government.
Let us hope that Gove and his cronies will have cooled down, with sedatives if necessary, in time for what Corbyn has described as a "pyjama party" of senior ministers at Chequers next weekend to thrash out the issue.
Indeed, there are some egos within the Cabinet so swollen you fear they might explode.
The "star turns" in this category are Johnson and the raw, brash Defence Secretary Gavin Williamson.
Only the other day Johnson made a very unministerial four-letter-word attack on business, which must have enraged the Prime Minister.
Lord Powell, who was Margaret Thatcher's foreign policy adviser, said the Iron Lady would not have tolerated Johnson's behaviour and would have sacked him.
Lord Powell said: "The idea that she would have tolerated Johnson's presence in the Cabinet for more than two minutes is absurd."
Meanwhile, Williamson should learn that you do not squeeze money out of the Treasury by threatening and shouting at the Prime Minister.
Williamson is showing all the characteristics of a callow, spoilt schoolboy.
At the forthcoming Cabinet get-together at Chequers, Mrs May will no doubt deflate these egotists, warning them to pipe down their public utterances - or else.