The long standing rule that debt cannot be enforced by imprisonment, save for the limited circumstances contained within the Debtors Act 1869 has been refined. In Hussain v Vaswani and others  EWCA 1216 Civ, the Court of Appeal endorsed the judgement of his Honour Judge Lethem, in the Central London County Court, and found that an ordinary debt could, if an undertaking was given to the Court be enforced for failure to pay the debt by way of imprisonment.
The Court of Appeal found at paragraph 46 that " As Bates v Bates makes clear, section 4 must be purposively construed. As Cotton LJ stated, its purpose is to prevent imprisonment for non-payment of ordinary debts. Thus, as the authorities make clear, it does not apply to orders or undertakings requiring the provision of security, whether way of payment into court or an appropriate bank account. I shall assume for present purposes that Luxmoore J was correct to decide in Cotton v Heyl that section 4 applies to an undertaking to pay money to a party which is otherwise precisely equivalent to an order to pay money to that party. I agree with Zacaroli J in Discovery v Jirehouse, however, that it is necessary not only to construe the undertaking, but also to take into account the context in which, and the purpose for which, it was given. In the present case, as counsel for the Vaswanis pointed out, Mr Hussain gave the undertakings in order first to establish a change of circumstances which would open the door to a reconsideration of the refusal of a stay and secondly to persuade the court to exercise its discretion in his favour by granting a stay. Thus the undertakings were the price Mr Hussain paid in order to obtain court orders in his favour and adverse to the Vaswanis. In such circumstances it is vital that the court should be able properly to enforce undertakings given to it. Mr Hussain did not comply with his undertakings. True it is that the non-compliance manifested itself in a failure to pay money to the Vaswanis, but in the circumstances that was not a failure to pay an ordinary debt. On the contrary, it was a failure to honour extra obligations to the court which Mr Hussain assumed, over and above the ordinary debts he owed, for the purposes of obtaining advantages in the proceedings."
This will be especially prevalent when possession claims restart. Individuals will be at real risk of giving undertakings to pay the backdated rent owed, in order to avoid possession claims, and fall into the position that they can be then imprisoned, until they pay that debt.
The issue is heading to the Supreme Court to consider permission, after the Court of Appeal granted a certificate that the issues contained within the judgement were matter of wider public importance.