Government business managers have refused to find parliamentary time for a Landmines Bill before the summer recess - and also given no guarantee that it will have top priority in the new session this autumn.
That raises the possibility that the landmines ban - championed by Princess Diana - will not be ratified for the foreseeable future, let alone by the anniversary of her death on 31 August.
Another casualty of the need for new legislation to set up a Northern Ireland assembly - assuming a "Yes" vote in this month's referendum - could be MPs' long summer break.
Government whips have already taken the unprecedented step of telling Labour MPs not to book holidays in August without checking with them first.
The delay over landmines, however, is causing particular concern to Mr Cook, who is committed to an "ethical foreign policy". He has refused to accept the ruling and, in frank correspondence with Leader of the House, Ms Taylor, appealed for parliamentary time before the summer break. One source claimed last week that the door was "still open" for this option.
Ms Taylor, who says she fully backs the measure, insists that there is no parliamentary time for a Landmines Bill. Mr Cook's second letter to Ms Taylor, however, again presses the case for ratification of the Ottawa Treaty before the summer break.
Foreign Office ministers have faced criticism from campaigners who argue that they are backsliding under pressure from the arms industry. Both sides of the argument insist that this is not the case and that the Government remains committed to the measure in principle.
After the death of Diana, Princess of Wales last year, Tony Blair was among world leaders who agreed to a global ban on landmines, an issue she highlighted in well-publicised trips to Angola and Bosnia.
The British Government was one of the first to sign the Ottawa Treaty to ban anti-personnel mines last December but now lags behind other signatories in drawing up legislation. This is crucial because parts of the treaty only become operational when they are ratified in law by domestic parliaments.
Failure to incorporate the ban into UK law also weakens the moral authority of the British Foreign Secretary as he seeks to persuade other countries to sign up. The Foreign Office's fall-back position is to secure legislation by the end of the year by getting the Bill introduced very early in the new parliamentary session.
However, Ms Taylor has been unable to guarantee any place for the Bill in next year's programme. That is because she does not chair the committee which decides which Bills will be included in the Queen's Speech.Reuse content