poor hot water flow at the kitchen mixer.

Hi,
This is my first thread and i would appreciate any advice as plumbing is not my strength.
My hot water is gravity fed from a tank in the loft and my upstairs hot water flow is quite strong.
As of about 6 months ago my hot water in the kitchen went from a steady flow to a trickle.
i've checked the inline valves prior to the tap and its fully open and i've also cracked the pipe off prior to the valve and flow is still a trickle.

thanx.

Probably an air lock. See the FAQ on how to clear it!

Cheers I`ll try and find some way of tracing it.