The Maritime & Coastguard Agency wants to listen in on telephone calls, read emails, be given access to itemised phone bills and also to be able to identify mobile phone users.

It wants these new powers in order to fight marine crime and ease the search and rescue procedure for those in trouble at sea, it says.

The Home Secretary Jack Straw has published a consultation paper which is inviting debate about the inclusion of public authorities – like the MCA – in being given access to communications data.