A perfect sausage needs a little care. This method works best with thick, English-style sausages.
Put a smallish pan over medium-low heat, only just large enough to fit the sausages. This helps the sides of the sausages to cook along with their bottoms.
Do not use a non-stick pan. It hinders the formation of tasty cooking juices.
Over a medium heat cover the bottom of the pan with oil, add sausages.
Turn constantly initially to brown the skin as evenly as feasible.
Treat them watchfully and you should be able to stop them curling, which makes even cooking then much harder.
Once the skin has stopped contracting you can relax.
Turn heat right down and fry very gently, uncovered, for up to an hour, turning now and again.
Do not prick. If they burst they are cooking too fast.