In Storm in the Village chapter 18, Rev. Gerald Partridge and Henry Mawne find Haricot Mutton on the menu at 'The Buttery', but as it is a hot day, they decide to have ham and salad instead.
It is one of the recipes included in Miss Read's Country Cooking
Haricot Mutton
1 1/2 - 2 lb middle neck, or shoulder of mutton
3 onions
clove of garlic
8 oz white haricot beans
dripping, stock, and 1 oz flour for gravy
8 oz peeled tomatoes (or a small tin)
Soak the beans overnigh - 24 hours is not too long.
Put them with plenty of stock or water into a deep casserole, with an onion stuck with 2 or 3 cloves. Let the beans cook gently in a very slow oven for 1 1/2 - 2 hours. Strain off liquor for gravy.
Now melt some dripping in a frying pan, flour the meat which is in small pieces, and fry with the onions until brown. Put them, with the tomatoes, into the casserole with the crushed clove of garlic.
Make a good gravy with the melted dripping and juices in the pan, the flour, pepper and salt. Any liquor from the beans can be used here. Pour over the other ingredients, cover the casserole, and simmer for a further 1 1/2 hours.