There are a number stages in the process the Council must undertake:
- First of all, the Council must obtain a "Liability Order" from the court. This instructs the debtor to pay.
- In the event of non-payment the Council must return to court and ask for a "Warrant of Control". This allows them to instruct bailiffs to secure payment and, if necessary, to seize control of goods to offset the payment (hence a "Warrant of Control.").
- If this fails to recover the sum, the Council must return to court. They will then seek the committal to prison of the debtor (who has now become "the defendant" in adversarial proceedings) for non-payment. The court must undertake a "means enquiry", looking into the debtor's means. When this has been completed, the court has to decide whether they find that either "wilful refusal to pay" (WR) or "culpable neglect" (CN) has been exhibited by the defendant.
"Wilful Refusal" is self-explanatory - the defendant had the means to pay but simply refused. "Culpable Neglect" means the defendant had the means to pay, but decided to spend his funds on something else and so is now unable to pay.
If the court finds either WR or CN they will be asked to make an order committing the defendant to prison. The period of imprisonment depends on the sum owed and the reasons the court found for non-payment.
In the first instance the court is likely to impose a suspended committal, ordering payment to be made (either in one go, or by instalments) as they think fit. In the event of failure to comply with that order, the suspended committal is likely to be enacted. It is important to be aware that, unlike committal for non-payment of fines (where the debt is written off by the time served in custody), in the event of committal to prison for non-payment of Council Tax, the debt remains outstanding on the release of the defendant.
In the event they find that the defendant does not have the means to pay, they have the power to remit (i.e. write off) some or all of the amount outstanding.
These arrangements apply to England only. In Wales there has been no powers to commit to prison for non-payment since 2019 (though the other provisions - liability orders and warrants of control - are available to the court). I've no idea what happens in Scotland.