What a sombre occasion. It was at once apparent that the Prime Minister’s voice had almost, though not quite, gone.

“Not again,” someone said, for we were carried back to her party conference speech in Manchester in October 2017, when her voice did repeatedly go, and it seemed as if she was going, as in a grand opera, to die on stage after a final, unconscionably prolonged and tricky aria.

“OK,” the Prime Minister replied, “you say that but you should hear Jean-Claude Juncker’s voice.” That produced murmurs of sympathy, but no lifting of the funereal mood.

She carried on, hoarse, croaky, sounding as if she really ought not to be performing public duties. “Most of us when unwell can take to our beds,” Anna Soubry remarked at the start of an intervention. “The Prime Minister just battles on.”

She did indeed carry on, and took an impressive number of interventions. But although she was immaculately turned out, in a red jacket and black trousers, she sounded like an invalid.

It was impossible to enjoy her performance. There was nothing in it to cheer anyone up. Nor did a number of helpful interventions by obscure Conservative MPs do anything to improve the mournful, valedictory atmosphere.

The Commons was far from full. As an orator, Theresa May is no great draw. Jacob Rees-Mogg had objected before she spoke to the allowance of only five hours for a debate on a matter of such importance.

He observed that “it isn’t wise”, and he disapproved of  “the element of bounce”, suggesting it would be counter-productive.

There was certainly no sense, as the Prime Minister spoke, that she was making converts to her vision of Britain as “a beacon of pragmatism”.

She added that “passionately held views do not stop us making compromises”, which is true, but how dreary she made her approach sound. “Responsible politics is about pragmatism,” she insisted, and no heart beat faster.

Up in the gallery, Philip May leaned forward with understandable concern. He was accompanied by Liz Sanderson, a member of the Number Ten press team. Only when his wife had got to the end of her speech did his face flush with pleasure.

In fairness to the Prime Minister, it should be said that the mood was sombre before she even entered the Chamber, as Geoffrey Cox, the Attorney General, made a statement on the legal opinion he has delivered on the revised deal.

There is nothing wrong with Cox’s voice. It is one of the finest instruments in public life. But from May’s point of view, there was quite a lot wrong with his legal advice.

Already, one felt one was observing a post mortem, to establish why the deal had died. Cox opined that various legal difficulties to do with the Northern Ireland backstop, though theoretically possible, were “highly unlikely” to arise.

But Chris Bryant, from the Labour benches, recalled that when he had suggested to Cox, three years ago, that he should become Attorney General, Cox replied: “Oh no, that’s highly unlikely.”

“And so it was under that Prime Minister,” Cox replied to laughter.

Bryant had, however, already made the point that in recent times, a number of highly unlikely things have come to pass, which means no one can predict with confidence what is going to happen next.

The Commons is in a state of deep trepidation. It does not know what is going to happen next. Joanna Cherry, for the Scottish Nationalists, told Cox: “The emperor has no clothes, none at all, not even a codpiece.”

That is not quite right, but there is a worn and threadbare feeling to the arguments made by May in favour of her deal, and even Cox, as he urged MPs to take the “calculated” risk of backing it, could offer nothing much in the way of new clothes.