Bangers and Mash is simply sausages served with mashed potatoes. Nothing exotic or complicated about it, but it's delicious, cheap, and filling. And very easy to make!
Preheat your oven to 210°C (410°F). Peel the potatoes, cut them into small chunks and place into a pan of boiling, salted water. When it comes back to the boil, turn down the heat and simmer until the potatoes are tender - about 20 minutes. Meanwhile place the sausages onto a baking tray in the oven and cook until browned all over - about 25 minutes. Turn the sausages every now and again so that they are evenly browned.
When the potatoes are cooked, drain off the water, add the butter, some of the milk, the mustard and a pinch of salt, and mash them. You want the mash to not be lumpy but to retain some texture.