Where are the Navy and SAS?

An Indian Navy ship this week blew a Somali pirate ship out of the water. This is wonderful news. Where however, is the British navy? This is our job, we should be sending the fleet to destroy pirate ships and protect trade vessels through the time tested convoy system. There are also British Subjects being held hostage by these pirates. Where is the SAS when you need them? It cant be that difficult to land a helicopter on an oil tanker.