Honest Burgers Warren St is a burger restaurant on Warren Street in London that serves beef and avocado burgers. Its main items include the Honest burger and a kimchi burger made with real kimchi, and the beef patty can be ordered medium. Fries come with the order at no extra charge and the portion is large, and every table is stocked with mayonnaise and ketchup. The onion rings are large enough for two people to share.