Events are running inexorably against Yahya Khan. The continuing American aid he set so much store by stopped dead yesterday. And China most devoutly touted of allies, has sent his emissaries home from Peking with the softest of comradely cotton wool - simply “sincere friendship” and “resolute support” over drinks at a state banquet. Not so much as a scrap of paper. Nothing remotely to keep Mrs. Gandhi awake.

India’s Prime Minister, in fact, has good cause for immense relief. Her world tour may not have produced tangible support on the required scale, but now she possesses promises to keep her warmongers at bay. Washington weaponry - a “major irritant” indeed - had become the symbol of Great Power ambivalence of Mr. Nixon’s increasingly harassed desire not to take sides in the subcontinental squabble. Of course nine million distraught and desperate wanderers were parked near Calcutta; of course democracy lay bleeding; of course army troops and hired gangs ran rampage; nevertheless Yahya was an honest man doing his best helping Dr. Kissinger’s travels. He must be given a trickle of spare parts for his tanks and planes, a trickle promising a flood if real war should start. Stemming this small flow makes little physical difference, but the new dam carries incalculable psychological weight. It means that the State Department has ceased balancing acts. It leaves Yahya without Western friends. It clears the way for further American pressure, the pressure which Bangladesh officials hope can finally overthrow Islamabad’s stubborn refusal to face facts and grant autonomy.

Where, then, can Yahya turn? Only to China, a dubious quantity on present evidence. Peking’s leaders had already been displaying vague unease about their curious championing of a right-wing Pathan field marshall even before Mr Bhutto arrived. That unease became manifest during the talks. All President Yahya can set against the Soviet-Indian treaty now is the expectation of continuing arms supplies - aid which makes him totally beholden to a Communist Government. There is no prospect of intervention against India if war breaks out. If war comes, indeed, Pakistan will be operatively alone, deserted and condemned.

The West Pakistan generals, in short, have come to the end of their path of bungling violence. They can battle and lose or talk and quit. They cannot hang on; they cannot erect a sham democracy - as the assassination of one of the East’s major sham democrats yesterday painfully indicates. Perhaps fresh negotiations with the Awami League and a released Sheikh Mujib would be impossible for Yahya personally. But he is always hankering for a return to barracks, and Mr. Bhutto would do the job more adroitly anyway: after Peking, he knows there is no true alternative.