Orange UK is moving to landline business, following "Ofcom's Wholesale Line Rental programme, under which BT is obliged to allow operators to offer both line rental and calls to customers over its network".
It looks like they are going to offer call charges 20% lower than BT, and discounted rates for calls between Orange landlines and Orange mobile number ranges.
Interesting move... I wonder if Vodafone will follow suit, first in Europe, then here?