I had an incident where I caught in a bad snow storm about 30 minutes after departure (met forcast did not predict it). I was going from Peterlee to Isle of man. 30 minutes from departure put me right in the middle of the Pennines. The freezing level was about 2000ft, so even VFR i would be winding down valleys. To top it off my VOR went down.
I never declared an emergency but I did ask Newcastle for RIS. As i was not Instrument rated and was outside of their airspace they refused. So i dumped them and called Teeside.
I explained the condition and they were more than happy to vector me to them. By this time the snow was really bad and it was almost dark.
Teeside radar handed me to Teeside tower who vectored me to just above 200ft until I became visual on approach.
My other option was to climb through the freezing layer and press on to the otherside of the pennines.
Teeside did not charge me for landing (even with RWY lights on!) and £4.23 for overnight parking. I got told to park with all the nice falcons and learjets and a man with a minibus picked us and took us to the terminal. The next day he dropped us off at the aircraft.
I guess I could have called a PAN PAN but I thought it would have been over kill. I went to pay the landing fee and expeted to get clobbered, instead what a lovely surprise...free. And with excellent service.