Apportionment
When you buy a property you'll want to make sure you only pay electricity, gas, council tax etc for the period in which you own the property. Therefore, these expenses need to be apportioned or shared between the buyer and seller of a property. In that way each party will bear his or her fair share at the date on which the property sale is completed.
The person doing your conveyancing, usually a solicitor, should be able to sort these details out.