About the Chicken Royale
The Chicken Royale costs £6.19 and carries 568 kcal. It is the longest burger on the Burger King UK menu, built on a breaded chicken fillet that runs past the edge of the bun at both ends, with shredded lettuce and mayonnaise in a sesame seed bun. There is no tomato, no onion and no ketchup, which is the point: it is a simpler burger than the Whopper and it tastes it.
The fillet is the whole thing. It is a long, thin, breadcrumbed piece of chicken rather than a thick nugget of breast, so the crunch to meat ratio sits high and every bite hits coating. That coating is seasoned rather than plain, and it holds its texture longer than most fast food chicken because the fillet is thin enough to cook fast without steaming itself soft.
Mayonnaise does the heavy lifting on flavour. There is a lot of it, and the shredded iceberg exists mainly to keep it from being cloying. Anyone finding it rich should ask for less mayonnaise, which is a change the counter will make without fuss and which takes a meaningful number off the calorie total.
At £6.19 it is priced level with the Whopper, so choosing between them is about what you feel like rather than what you can afford. Against the specialist chicken chains it competes on price and loses slightly on coating crunch, though it wins on portion length. The double version adds a second fillet for people who find one too light.
It works best eaten immediately. The coating softens under the mayonnaise faster than a beef patty degrades, so a Royale taken home is a noticeably worse burger than a Royale eaten in the restaurant. Order it with fries rather than a heavy side; the burger is already carrying a lot of coating.