I had this "crackling" on the line (BT landline) so I rang the BT Engineers to report a problem. A lovely BT engineer came around and put a new junction box in for me - problem solved (the new one also had an in-built filter for broadband, so I could get rid of the plug in filter too). No charge either !
No sure what you do if your landline isn't with BT though.
wen i speak to my dad the line crackles more often than not. it happens when he's sitting in the conservatory next to his standing lamp that he uses to read with. when he moves away from it, it stops.
Thank you all very much for your help and suggestions.
I think my broadband modem is the cause since crackling stops when modem / phone link disconnected.
However, also noticed that my modem running warm (more than usual) so am getting a new one - and keeping my fingers crossed.
Try ringing 17070 from your phone and listen to messgae and press 2 i think for a quiet line test. I f you hear fuzz then it is the line and ring 0800 800 154 to report a fault (if with BT). If line is ok try another phone in the socket and see if it is the same if the noise goes it probably is the handset, also if you are standing near heavy machinery (unlikely( this will have an affect.