Mobster, I think you, me, 74F and Phileas all work for the same happy family.
I know exactly what you mean, as we are regularly rostered standby duties before and after flights. This was brought formally to the CAA's attention and also to BALPA.
As usual, utter lack of interest from the CAA. BALPA's point of view was that it is perfectly legal, although poor practice. Considering who we work for, a fair enough answer I think.
As for Phileas's rather smug comment of - you can go home and have a nice cup of tea - well, you might if you happen to live 5 minutes away from Mersey Base. However, more than half the aircrew operate out of other bases and traditionally (and occaisonally due to the company) live much further away, making it very impractical to go home for this 3-4 hour standby.
It's not very pleasant spending 3-4 hours in our Midlands facility offices, especially as the CAA have said it is not fit to be used for split duties.
As the folks at BALPA told us, legal but not particularly ethical.
Oh, and as I think Phileas is management, I'd let this subject drop quietly!