On 06/01/12 17:58, Charles Ellson wrote:
Mercury was not providing the infrastructure for that service, merely
using an established provider to connect the calls to their much
smaller network, a bit like Sainsburys being obliged to allow a
competitor to set up order desks within its premises.

I believe that the original Mercury 131 service required Mercury to have
lines into BT exchanges. When I signed up in 1992 only some areas of
Edinburgh were covered. The later 132 service was much more like things
nowadays, and was available from any BT exchange.

Ian