According to the publication, EU countries can put forward their proposal and postpone the deadline for Brexit on May 22.
The prime minister is seeking an extension of the negotiating period to 30 June to allow the necessary legislation to be passed should she finally get MPs to back her deal next week.
“The 22nd of May has to be the limit,” one senior diplomat said. “The reason is that there has got to be a very clear message from the European council. Yes to a short extension on condition that the prime minister passes her deal through the Commons. But beyond that it is utterly complicated. It cannot be done without British MEPs having been elected.”