Political column March 15

But Jeremy Corbyn was not on the bus.

The statement made by the Prime Minister must have been one of the most serious in modern times short of a declaration of war.

In the face of the use of a military grade nerve agent - an illegal weapon of mass destruction - on the streets of Britain, there was no shillyshallying, no mealy-mouthing.

The Russians had treated the matter with sarcasm, contempt, and defiance, she said,

"There is no alternative conclusion other than that the Russian state was culpable for the attempted murder of Mr Skripal and his daughter and for threatening the lives of other British citizens... This represents an unlawful use of force by the Russian state against the United Kingdom."

The measures she announced included the expulsion of 23 Russian diplomats, or perhaps they should be termed so-called diplomats as she said they were undeclared intelligence officers, the suspension of high level contacts, and the withdrawal of dignitaries and members of the royal family from the World Cup.

In response Jeremy Corbyn condemned the Salisbury attack as an appalling act of violence and said the use of nerve agents was abominable.

Our response must be decisive, proportionate, and based on clear evidence. Had she responded to the Russian government's request for a sample of the nerve agent? It was essential to maintain a robust dialogue with Russia.

It was a matter of huge regret that Britain's diplomatic capacity had been stripped through government cuts.

This was too much. MPs were by now very restless and Boris Johnson said something.

"I couldn't understand a word of what the Foreign Secretary just said but his behaviour demeans his office," said Mr Corbyn.

That sparked off yet more noise and heckling.

Mr Corbyn continued in similar vein, working the House, or rather working up the House, as it turned out.

Russian oligarchs were using London to protect their wealth. We needed to build an international consensus. What discussions had she had? He paid tribute to human rights campaigners in Russia.

It was all a throwback to those 1980s days when Mr Corbyn was an awkward squad backbencher. Trouble is, he is now a leader, and the Prime Minister in waiting.

Mrs May pointedly said in reply that there was a consensus across the backbenches.

"I'm only sorry that the consensus does not go as far as the Right Honourable Gentleman..." (great noise and hubbub) "...who could have taken the opportunity, as the UK government has done, to condemn the culpability of the Russian state."

Ian Blackford, the SNP leader in Westminster, and not exactly the Prime Minister's greatest supporter, welcomed the measures and gave his support.

"The only response today must be a robust one towards the Kremlin and to Russia," he said.

The cheers and hear-hears gathered volume, being clearly partly intended for Mr Corbyn's ears.

For Labour, the contributions from the backbenches heralded a revolution - a rebellion against the Labour front bench before our very eyes.

One by one they got up to support the Prime Minister's statement.

Tory MPs condemned Mr Corbyn. Anna Soubry said it was a "shameful moment" while Mark Francois said: "He remains at heart what he has always been - a CND badge-wearing apologist for the Russian state."

And for those who have been puzzled as to why the Salisbury attackers used a nerve agent - which has not proven fatal at the time of writing - rather than a more prosaic but proven-as-effective method of murder, Ken Clarke had the interesting theory that it amounted to a show killing.

"The choice of this particular bizarre and dreadful way of killing an individual is a deliberate choice of the Russian government to put their signature on a particular killing so that other defectors are left in no doubt that the Russian government will act if they're disappointed in any way by their actions," he said.

The Prime Minister summed things up: "This is an important moment to stand up and say to Russia, No, you cannot do this."

There is an old saying that when the House of Commons agrees on something, it is always wrong.

Yesterday it mostly agreed - with the exception of Mr Corbyn and his silent front bench colleagues, who are not sure.

History will tell us where the wisdom lay.