Not paying debts has been decriminalised. You can't be convicted of a crime for not paying a debt, with the exception of the TV licence (and maybe debts to HMRC). You can be convicted of a crime for breaching a court order requiring you to pay a debt, but that's a conviction for contempt of court, not for not paying a debt.

However, there's a good reason for this, which is that in any other case, the creditor can stop providing the service to the defaulting debtor. Not so with the TV licence, which is why it deserves to be a special case.