running tap

[AnonymousImport]

Just had a new kitchen sink fitted -great-however got a problem. When all the taps are off everything is ok but if I run the hot taps upstairs the kitchen mixer tap starts leaking water ,even thou the mixer taps are fully off.When the hot taps upstairs are switched off the tap downstairs stops running.WIERD!!!
Any help would be gratefully received

 

[AnonymousImport]

Does the tap leak hot or cold water?

 

[AnonymousImport]

hot water

 

[AnonymousImport]

the tap cant leak water unless it is faulty

 

[AnonymousImport]

Cannot understand if its faulty ,why it dosen't leak all the time..