My washing machine is placed in my kitchen and whenever it is switched on and working (washing), I get very mild “tingles” from the kitchen's tap water. I'm in the UK, and I've checked that the wall socket is earthed and the machine's plug is also earthed. I'm not using any extension cables. What else can I check before calling an electrician? If possible I'd like to fix this problem myself. Thanks!
EDIT 1: My house was built on the 70s.
EDIT 2: I asked an electrician to fix the problem and he said the following: two of the earth wires were in the correct position but one had no earthing sleeve on it and was pressing on the live wire. The third earth wire was not connected at all and there was a small voltage showing, but not enough to trip the switch. He re-routed all the wires and attached the loose earth wire and all is now fine!