A statutory demand is a formal written demand for a debt of £5,000 or more (company) or £5,000 or more (individual, as of October 2023 uprated threshold). If the debtor does not pay, secure the debt, or compound within 21 days, this creates a presumption of inability to pay debts — allowing you to petition for winding up or bankruptcy.
Legal reference: Insolvency Act 1986 ss.267-268 (individual), s.123 (company); Insolvency Rules 2016