My Lords, I am sure the Russians are in no doubt of the capability that the Royal Navy can demonstrate. The Royal Navy has a robust range of measures in place for detecting and shadowing non-NATO naval units which may seek to enter our territorial waters without prior authority. We continue to develop new detection capabilities to maintain the operational advantage that we need. The strategic defence and security review currently under way will allow us to assess the full spectrum of submarine detection capability, including the utility of fixed-wing maritime patrol aircraft.