Bring the water to the boil and add the crab, salmon bones and salmon. After 5 mins remove the salmon and leave to cool. Simmer the crab and the bones for a further 15 mins, then melt the butter and add the onion. When the onion has softened (4 or 5 mins) add the flour and cook on a low heat for 2 mins then add the tomato puree. Start to add small quantities of the fish stock stirring to make a smooth soup, bring to the boil and simmer for 20 mins. Meanwhile remove the brown crab meat and add to the soup. Flake the salmon and keep for garnish. Retain the white meat from the crab claws for garnish, the shell can be broken up and added to the soup at this stage to add more flavour. Strain the soup through a fine sieve and return to the stove and add the leek, simmer for 5 mins and seaon with the ground pepper, salt and cayennes pepper. Add the cream and salmon and lobster garnish. NOTES : A rich extravagant soup for a special occasion