I have just got back from a weeks holiday, and the cold water tap on the bathroom sink is acting strangely.
When I turn it on, nothing happens for about 5 seconds, then it starts to trickle, gradually getting to full flow after about 10 seconds.
If I then turn it off and turn it on straight away it's fine, but if I leave it off any longer than a minute or so, it will do the same again.
Very occasionally I turn it on and it's full for about a second, then drops off before going back to a trickle and then back to full.
This tap is mains fed, I don't have a cold water tank. Normally this tap only needed a single turn to be on quite fast, and turning on full gushed out far too fast and splashed everywhere. No other cold taps in the house seem to be affected, although the main bath tap may be slightly lower pressure than normal.
Anyone have any ideas what could be causing this?