GPS shouldn't be used as a primary means of navigation anyway, so its irrelevant.
What a load of uneducated tosh!!
GPS can and is used as a PRIMARY means of navigation. Above FL95 in a light aircraft it is pretty much the only means of meeting the BRNAV compliance.
NATS and the other European ATS providers are currently looking at turning of the conventional navigation aids in preference for BRNAV systems. Take a look at the current consultation that will see nearly half the VOR's and all of the enroute NDB's turned off in the next couple of years.
Whatever the old guard may think, GPS is here to stay and we will all have to come to grips with it as a primary means of navigation. Any Instrument pilot, IR or IMCr should be embracing current technology and any Instructor teaching for such ratings is doing the student a disservice by not teaching current technology.
The AOPA RNAV course is currently being updated to cover GPS and this can be linked to the IMCr for full credit. We tried to update the IMCr a couple of years ago but with the transition to EASA it was put on the back burner.