If I don't pay for a utility bill, can EDF Energy disconnect my?
In practice they would almost certainly replace your meter with a pre-pay one, meaning that you would have to buy credit in advance to get electricity: no credit, no power. As Harry Linfield reminds us, the cost per unit of pre-paid electricity is higher than buying it the usual way: however your meter will be set to charge you more than this (per unit) so that your debt to EDF is gradually paid off.