Tuna pasta bake

1 onion finely sliced
2 carrots chopped into small chunks
1 clove crushed garlic
1 tbsp olive oil
1 400ml tin chopped tomatoes 
2 tsp dried herbs
Worcester sauce
1 large can tuna chunks
2 handfuls of spinach
10 oz dried pasta 
2 packets of crisps
Grated cheddar cheese

1) bring to boil a large pan of water, add the pasta and chopped carrots and cook for 10 mins until al dente 
2) meanwhile gently fry the onions and garlic in a large saucepan for 2-4 mins then add the tomatoes, splash of Worcester sauce and herbs and leave to simmer for 10 mins until reduced. Stir in the spinach and stir until wilted then add the tuna. 
3) drain the pasta and stir into the tomato sauce. Transfer into an ovenproof dish, sprinkle with the crisps and top with the cheese. 
4) pop under a hot grill until the cheese has melted and golden.