The Fryer's Delight on Theobald's Road might have black or white pudding on the menu. I haven't called in for a number of years since I no longer eat beef, pork or chicken and the shop fries in dripping, but they might be able to fulfill your needs.

No London chip shop has offered anything close to the delicious meal I had at the International in Kirkwall, but Micky's Fish Bar (temporarily closed for refurbishments) and Faulkner's on the Kingsland Road aren't bad.