It was bound to happen - 1 day before "The Day Of The Doctor" when the 50th anniversary episode of BBC's television programme "Dr Who" is shown simultaneously in over 80 countries - Royal Mail has apparently actually mastered time travel itself. Since the company has been criticised for not achieving its targets on promptness of delivery of first class local mail (it has not managed to deliver 93% or more of first class mail the day after it was posted), this achievement of time travel will no doubt come as a surprise to many people.
But here's the evidence - the postman has just delivered a cover being sold by Royal Mail to commemorate the precise 50th anniversary day of the first broadcast of Dr Who (23 November 1963). The cover has 11 Doctor Who stamps attached to it and is cancelled by a circular blue postmark which depicts Dr Who's time travelling machine, the TARDIS, with "50 YEARS" inscribed on it and at either side the dates 1963 and 2013. The inscription around the edge reads "50TH ANNIVERSARY OF DOCTOR WHO BBC LIME GROVE STUDIOS, LONDON W12" and at the bottom, the date "23.11.2013", presumably indicating the date the cover was posted. Since the cover has been delivered one day before the date of the postmark - that is - on the 22 November 2013 one can only conclude that this represents a documentable example of real time travel.
Well, I guess not. It's just a commercial souvenir where no care has been taken to even give the semblance of real postal use but it's all a good bit of fun and no doubt this particular item will give a lot of pleasure to the enthusiasts for Dr Who whose purchase of the stamps and associated philatelic products have made the issue a great financial success for Royal Mail during 2013. Perhaps some of the profits can be used to increase the chance of ordinary mail being delivered on time. Or perhaps, now that Royal Mail has mastered time travel, that technological achievement will help speed up the posts.