Chef Serin Aubrey of Anzac Street Bistro in Dartmouth, Devon gives us his Sauce Vierge for fish and shellfish:

Ingredients:
1 tbsp coriander seed
1 clove garlic
1 finely chopped shallot
2 plum tomatoes
1 tbsp chopped basil
1 tbsp chopped coriander
juice of 1/2 a lemon
sea salt and black pepper
6 tbsps of extra virgin olive oil (to quote Serin: of the best extra virgin olive oil known to man, only available from Dina at Oil in the Raw)!

Method:
Toast then crush in a pestle and mortar the coriander seed.
De-seed the tomatoes and chop into 2cm dice.
Crush the garlic clove and add along with the shallot and coriander seed to the tomato in a mixing bowl.
Add the chopped herbs, lemon juice and salt and pepper to taste.
Finish with the olive oil and leave for an hour or so to let the ingredients infuse.