The UK domestic supply has a potential difference (p.d.) of about 230 V between the live wire and the neutral wire. The live wire is at an alternating p.d. of about 230 V compared with the ground.
The neutral wire is close to zero volts (0 V). It is connected to earth at the supply, so the p.d. between neutral and earth is about 0 V. The earth wire is also at 0 V.
This is why the live wire is dangerous. A p.d. of 230 V between the live wire and a person standing on the ground can drive a current through the body. Touching the neutral wire or the earth wire does not do this, because they are at about 0 V.