I needed to send some important original documents through the post so went to the Post Office on Wednesday afternoon and told the bloke behind the counter, "I want this to arrive by tomorrow and I need proof of posting." I didn't tell him that I actually had a Friday deadline - I was leaving 24 hours breathing space in case Royal Mail cocked up, allowing me time to print off scanned copies and take them personally (they wouldn't be originals as required but, with the proof of posting, at least it would show good intent on my part). I was duly offered their "Guaranteed by 1pm next day delivery with Track and Trace." Sounded good, so I handed over the envelope, paid my £6.25 and wandered off. Yesterday, as a result of a nagging doubt, I decided to check on the progress of the documents. At 1pm, the on-line track and trace registered that they had been received at the post office and were somewhere in the system. Uh oh. They should have been delivered by then. Now, I'm a fairly lenient and understanding sort of bloke. Postman Pat might have phoned in sick so the document could have been tagged onto Postman Fred's round, delaying it. Or his van could have had a puncture. Or maybe the system takes a while to record a successful delivery. Besides, I wasn't worried about it arriving by 1pm, I'd stipulated Thursday and anytime on Thursday would have done. I rechecked at about 6pm and received the same information - still in the system. Starting to worry now. I checked the Royal Mail website, finding a caveat that the item had to be posted before the "final acceptance time". No information was forthcoming about when that time was but a glance at my receipt indicated "Posted after last collection - No". At 10pm, the Track and Trace message indicated that the documents had progressed further through the system and "would be delivered by the guaranteed time of 1pm on Friday". This triggered emergency action planning - as it would take me about three hours to make the journey in person and another three hours to print off and collate the documents, I had a deadline of 11am for the Track and Trace to confirm delivery. Even then, if the recipient decided to be snooty about them not being originals, I could end up with a consequential loss close to the Royal Mail's £10,000 compensation maximum. I checked Track and Trace this morning to be presented with the joyful notification that the documents had been delivered and signed for a few hours earlier, "before the guaranteed time of 1pm". Now just a minute. The guaranteed time may well have been 1pm, but the guaranteed day was Thursday, not Friday. And the points of despatch and receipt were both on the Greenwich meridian, so no excuse of crossing the International Date Line. So, a warning that if you're posting important documents by a Royal Mail guaranteed service, take into account that their calendar doesn't follow the Gregorian format.