EU consensus needed to scrap UK vote

From the Scotsman again:

"THE British vote on the European constitution can only be scrapped with the agreement of other European Union leaders, Downing Street admitted yesterday."

Eh? I have to say, I don't get this: the constitution has to be ratified by all member-states; one of the most important has rejected it and the French Prime Minister said there was to be no second referendum; and another of the founding 6 looks likely to reject the constitution today. So what possible reason can there be for having one here?