The company missed an Oct. 31 deadline to pay a Renewables Obligation (RO) bill totalling 530,809.20 pounds despite multiple reminders, a final order, and accruing late payment interest, Ofgem said.

Delta now has 21 days to respond to Ofgem's notice of intent, after which an official decision will made on whether to issue the penalty, the regulator said.

"Compliance and enforcement engagement is a resource and time intensive activity, and we take a very dim view of any repeat offenders," Ofgem said.

It is the second time energy supplier, which serves 1,690 business customers in Britain, has been subject to enforcement, after late payment for the 2020/21 period as well, the regulator said.

($1 = 0.8073 pounds)

(Reporting by Nora Buli in Oslo; Editing by Mark Potter)