I think i know where DIRRIK is coming from.
Say the cessna 406 turboprop, which is single crew.
Under JAR-ops for it to be operated as single crew IFR it must have a functioning autopilot.
Now if the AP is US JAR-ops states that it must have 2 IR qualified pilots on board. It dosn't stipulate that both pilots need to be type rated or even the second pilot a CPL holder.
I don't have a clue if you can log it or not.
There are quite a few corp operators out there fly with what appeares to be 2 crew on board in white shirts because the punters like to see 2 pilots. But in reality there is only one person type rated who is operating the machine the other is there for show. I believe the going rate is about 50-60 quid a day for ironing a shirt and pretending you know what you are doing.
You definatly can't log this flying even if you are lucky enough to have a pole about.
Personally I wouldn't put the time in your log book in the first case because it looks a bit daft if on your CV if you are claiming turboprop time while not holding a type rating. Use it as a method to keep current flying IFR. Maybe bring it up at interview to show that you havn't been sitting with your thumb up your bum waiting for a job to fall in your lap.
While working at xxx flying school i was lucky enough to be allowed to fly as second pilot on xxx. And if you were allowed to fly some procedures and TO and landing but don't lie. More than likely the interviewer will know someone from that company and will phone up asking what your flying was like. The network in the UK is unbelievable and especially in the corp and regional airlines the fleet captains and ops directors all know each other.
MJ