Preheat the oven to 180˚C fan / 200˚C / 356˚F convection / 392˚F.
Cook the pasta in boiling water according to packet instructions less 1 minute. Drain.
While the pasta is cooking, make the sauce:
In a medium saucepan melt the butter or margarine over a medium heat. Once melted, add the flour and stir until well combined.
Cook for 2-3 minutes, stirring, then slowly add a little of the stock / milk, whisking with a balloon whisk in between each addition.
Once all the liquid has been added, cook for 4-5 minutes, whisking, until the sauce starts to thicken.
Take off the heat and add the Worcestershire sauce (if using), 1 c grated cheese, drained tuna and sweetcorn and season with black pepper.
Add the drained cooked pasta and stir to combine.
Tip the mixture into 11 x 8 inch oven proof dish. Sprinkle over the extra ¼ c grated cheese, if using.
Place in the preheated oven and cook for 30-35 minutes until golden and bubbling.
Leave for a couple of minutes before serving - it’s hot!