You might think that but I think you are wrong. Lots of people say it, but I have carefully read the Electricity Act a number of times, and interfering with the fuse is not specified as an offence (there are offences relating to interfering with the meter and certain other acts though, depending on what else you do).totally correct its an offence to tamper with the equipment supplied by the network, this does include the service fuse.
There is a difference betwen a criminal offence and a breach of contract.