RotgerF
Thank you for the link, I found it at
http://www.ais.org.uk/aes/pubs/aip/pdf/aic/4P041.PDF
It states that you can use a GPS so long as it does not replace conventional nav techniques. That is pretty obvious - one always needs a backup, either visual in VMC or VOR/DME in IMC.
It does not say that a GPS cannot be used as a primary navigation aid, and indeed almost everybody who flies modern well equipped planes does exactly that. Anything else is just unnecessary extra workload, and much less accurate.
I do read all the publications I come across, and the accident reports are always interesting. But a lot of the stuff in the GASIL wad which came through the post the other day appears to be written by old codgers who would regard a PA28-140 with a VOR receiver as a "modern" aircraft.