There are two reasons that England played in purple that day
1. It's a long-standing tradition that in rugby the home side wears a different strip when required due to a colour clash. It is the hospitable thing to do after all.

2. Having decided that, despite it never being a problem in the previous ten or so games between the two sides, white is indistinguishable from blue and white hoops, somebody saw an opportunity to sell more merchandise.
(Vice Admiral Sir Charles Cockbrush KCB MBE DSO, who is finding it increasingly difficult to log into b3ta.com wants to duck your aunt and kick your puppy, Fri 5 Feb 2010, 14:45, 1 reply)

Well it did appear thus to me...
...but there was a large amount of gumpf about the "return to royal purple" or somesuch bollocks.

In fact it was much like this press release from Nike:
www.rfu.com/News/2009/October/News%20Articles/291009_Eng_Change_Kit.aspx
( pixel_fucker is going to need a bigger brush, Fri 5 Feb 2010, 17:55, closed)