Cook the spaghetti for 12 mins, or following pack instructions, until al dente. Meanwhile, heat the oil in a large frying pan, add the leeks and chilli and cook for 5 mins. Stir in the garlic, peas, lemon zest and juice, then cook for a few mins.

Drain the pasta, then add to the pan with 1/4 mug of pasta water and the crab, then toss everything together until well coated. Spoon into shallow bowls and serve.