Chefs searching for an authentic medieval way to roast a porpoise can now look up the recipe online.

The Forme of Cury, compiled by master cooks to Richard II, is part of a collection of medieval texts held by the John Rylands Library, Manchester.

Now an edition of the cookbook dating from the early 15th Century, compiled in about 1420, has been digitalised and uploaded to the library's website.

John Hodgson, keeper of manuscripts, said it contained hundreds of recipes.

Among them are exotic dishes featuring porpoise and more recognisable names like blancmange.