The leading brown sauce in Britain is HP. The leading brown sauce in the US is A1.
Broadly speaking, A1 is a cross between HP Sauce and Worcestershire Sauce. HP is sharper and thicker, whereas A1 is a little more fruity. You can find the imported American sauce in larger Tesco supermarkets in the UK. It pairs well with beef, especially in casseroles and meatloaf.
A1 is a British invention, introduced by Henderson William Brand in 1862, when he was co-manager of the cuisine at the International Exhibition in Hyde Park. He submitted the sauce before the Royal Commission for use in the Exhibition’s restaurants. The Chief Commissioner reportedly declared the sauce to be “A.1.”
Gilbert Heublein (1849 – 1937), a German-born spirits distributor resident in Connecticut, visited England and encountered A1 sauce. He was impressed, and after much effort he acquired the exclusive US distribution rights to A1 sauce from 1894. He gained the US production rights from 1916.
A1 was phased out in Britain in the 1970s, forced out of a crowded brown sauce market which included HP, Daddies and supermarket own-label nationally, as well as OK, Heinz Ideal, Hammonds and Fletcher’s Tiger Sauce at a regional level.
The brand is currently owned by Kraft in the US. In Britain, the trademark is currently owned by Premier Foods.