Wash the clams and mussels under cold running water, discarding any that are broken or that remain open when tapped. Pull away the 'beards' from the mussels and scrub well. Soak the clams and mussels in plenty of cold water for 30 minutes, then drain and rinse again in cold running water. Put in a bowl, cover with a wet tea towel and refrigerate until required.
Heat the oil in the largest frying pan you have or a wok over a low heat. Add the garlic and chilli and leave the flavours to infuse for 10 minutes. If the garlic begins to colour, simply remove the pan from the hob and leave to infuse in the heat of the pan.
Cook the pasta in a large saucepan of salted boiling water according to the packet instructions until al dente.
Meanwhile, increase the heat under the frying pan. Add the wine and boil rapidly for 2 minutes. Add the clams and mussels and cook, stirring, until they open. This shouldn't take longer than 4–5 minutes.
Drain the pasta and add to the frying pan with the parsley. Toss over the heat for 30 seconds, to combine all the flavours. Serve immediately.