mixer tap - cold tap turns on but only a dribble comes out

[clareada]

we have an Ikea mixer tap in our kitchen. Hot water tap works fine, but the cold water had a day or two of less water coming out and now it is just a dribble. The tap turns fine. If anyone could advise on how I remedy this that would be great!

 

[Armo74]

Is the problem only with this tap?
Is it a quarter turn tap?
If not isolate the water supply and strip the tap down the jumper maybe stuck down slightly.

 

[clareada]

yes, it's only this tap and it's not a quarter turn tap. Tap turns full on as normal, but just no water. Hmmm. So take it it's not the jumper then...Any other ideas?

 

[picasso]

As said the washer may have detached from the tap body and is stuck on the seat, switch the water off and dismantle the tap is the only way to check.

 

[clareada]

I've taken it apart so far and what I can only describe as a minimini bicycle clip was a little mangled looking so removed it and put a new one in. It's now a bit more than a trickle, but not full flow. But it is just about useable for now and also, note, the water comes out when I turn it half on. When I turn it full on, the water stops coming out. Hmm. Though the thread feels fine. I spoke to the guy in B&Q and he reckons we need a new tap. Hmph. But I am determined - it's only 3 years old!!!
I am thinking I should strip it down further (couldn't actually figure out how to do that with our particular taps), but then again the fact that whatever I've done has effected it a little, makes me think it's something nearer the surface. Thanks everyone for your help so far.
Do let me know if you have any other ideas as v helpful so far!