Regulation 2(1)(a) of the Discretionary Financial Assistance Regulations 2001:
(a) are entitled to housing benefit or a relevant award of universal credit …
I don't think it makes as much difference as people make out. You are only entitled to a benefit when a claim has been put in and a decision made on that claim. The DWP used to always confuse this in JSA by talking about underlying entitlement.
