Supplier discretion in switching with a debt
There is nothing to prevent a supplier allowing you to switch if you have arrears. However, you may be required to pay what you owe before you switch (see here). The decision to take on a customer with an existing debt is at the discretion of the company, and several suppliers appear willing to take on consumers who may have been previous customers and who have had good payment records. Switching supplier may also be a method of preventing disconnection from another supplier to whom a debt may be owed. If you use a prepayment meter and have a debt of less than £500 per fuel, you may be able to switch to another supplier, taking any debt with you (see here).