Switching when you owe money
In many cases, yes. Owing your current supplier money doesn't automatically block a switch, though the rules differ depending on how much you owe, how long it's been outstanding, and whether you're on a prepayment meter or standard billing. This guide sets out how those rules work and what actually happens to your credit file when you switch.
Switching itself doesn't affect your credit score
The act of switching supplier isn't a credit event and doesn't appear on your credit file. What can affect your score is what led up to it: missed payments and defaults on your current account may already be recorded with credit reference agencies, and those stay on your file regardless of whether you switch or not. A new supplier may run a credit check as part of signing you up, which is a normal part of opening any new account, but the switch itself isn't what causes any impact.
Prepayment meters: the Debt Assignment Protocol
If you're on a prepayment meter, Ofgem's Debt Assignment Protocol (DAP) is the specific mechanism that lets debt move with you when you switch. Ofgem raised the DAP threshold from £200 to £500 per fuel, meaning your existing supplier must facilitate a switch and transfer debt up to that amount to your new supplier, rather than blocking the move outright. If your prepayment debt is above £500 per fuel, you'd typically need to bring it down below that threshold, or agree a repayment arrangement with your current supplier, before a switch can go ahead.
Standard billing customers
For households on standard credit billing rather than a prepayment meter, there's no single fixed monetary threshold in the same way. Suppliers can generally object to a switch if you have debt that's been outstanding for some time, commonly cited as around 28 days, though practice varies by supplier. Being in credit, or having a recent bill you haven't paid yet, isn't the same as being in debt for switching purposes. If you do have older arrears, contacting your supplier to agree a payment plan is usually the fastest route to becoming eligible to switch, and suppliers are required to offer a plan based on what you can reasonably afford.
What a supplier can and can't do
A supplier can object to a switch on the basis of genuine unpaid debt. What they can't do is block a switch simply because they don't want to lose you as a customer, or because of a charge you're actively disputing. If you believe an objection is unfair, it's worth raising it directly with the supplier first, since objections need a valid reason behind them.
If you're struggling to pay
If the underlying issue is that you're finding it hard to keep up with payments generally, that's a different question from the mechanics of switching, and it's worth addressing directly rather than working around it. Our sister site energyBillSupport has guides on energy debt options and the household support fund, covering the support schemes and repayment routes available. Free, independent debt guidance is also available from StepChange and Citizens Advice.