QUOTE(Guest @ Oct 31 2008, 01:25 AM)

It's not exactly the most taxing part in the west end... why can't she do eight shows a week like everyone else, especially after how many times ALW said mentioned to every Nancy contestant "I wonder if you can do 8 shows a week?".
"It's not exactly the most taxing part in the West End..".
It is obvious from that comment, you have absolutely no experience or knowledge of theatre. The role of Nancy is an extremely taxing, emotional role, which requires a great amount of stamina, talent and experience to fulifill.
While Jodie is obviously very talented and I'm sure will do a fantastic job, it is not unusual to have an alternate perform scheduled shows in a large scale musical like Oliver!.
I also think it was a very smart move by the producers. Considering this is the biggest role/show Jodie has ever worked on, she probably won't have the stamina to sustain 8 shows a week, at least initially. Her stamina will improve, absolutely, but being able to rest 2 shows a week will no doubt mean she will be "on" more often than "off", which in turn benefits the audiences who would like to see her perform the role.
This leads to another advantage for audiences: if an actor needs to have a show off because of illness etc, and the understudy goes on, the audience have no prior notice. With an alternate, the shows are scheduled, therefore audiences can decide which performer they would like to see (in this case, Jodie or Tamsin) and book tickets accordingly.
I hope you now have a greater appreciation of this industry, its demands and workings.