Update: Here's your answer.
Well before we knew anything about WWE needing a new world champ, we knew that Undertaker was being flown to the United Kingdom to add star power to tour that was already missing John Cena, Daniel Bryan and Randy Orton. But the initial announcement was for a SmackDown appearance only.
But with Seth Rollins added to the list of missing Superstars after his knee injury in Ireland last week, it looks like the company is at least keeping the option of using The Phenom on tonight's show. Multiple fans on site are reporting that Taker travelled with the roster to the Manchester Arena.
There are, of course, plenty of possible explanations for this that don't involve a television appearance for The Dead Man on tonight's show. He could be filming backstage segments for tomorrow's taping/Thursday's broadcast, or just being a locker room leader and showing up to support the guys and gals from behind the scenes.
But with interest in today's episode of Raw at an all-time high due to the announcement that the world title tournament will kick off there, the possibility of Taker's first appearance since being carried off by The Wyatts at Hell in a Cell is even more intriguing than normal.