How do I connect a normal sink tap outlet to a WC cistern 1/2 float valve?

[Shires Lynx]

the issue is that you are asking for advice on how to connect something to the water supply that is slightly out of the ordinary. there are regulations in place to ensure the water supply does not get contaminated, what you suggest seems worrying.
if you gave more of a description as to why you want it to work perhaps the replies may be closer to what you wanted.
the process of making the connection you want is very simple, the issue is whether you should make it.

Well I did say in my original post I am a cistern collector, and just have a general interest in seeing cisterns work the way they should. That's why I want to connect a water source from a sink tap to the actual float valve instead of just getting a jug and filling the cistern up.

It's just a hobby - nothing serious and will not be used for anyone else nor by anyone else.

 

[dancinplumba]

there is also a concern with regard water conservation imo, there is serious watershortage in the south east and lincolnshire

 

[moore]

hi mate - this is an interesting situation, please forgive my asking, but if youre a cistern collector, would you think it a better idea to tee off from the cold supply to your sink - and run a 15mm copper pipe to a clear area,(clipped to the wall).... isolate it with a stopcock / tap / valve- then atach a flexi compression tap connector to it.....then you can test them whenever you want, keep the facility of 2 taps on your sink etc - the look of your desired tap to cistern scenario makes me think youll get wet, and if youre planning to keep the tap in the open position - your home will get wet / damaged too - if you dont know about plumbing - get a plumber round to have a look - im sure it wont cost that much, i say this to you out of honest politeness mate pls be careful!!!
ps put some pics on, of your cisterns, have you any old / rare? - moore