I agree there should be full transparency over any plans for such a database.
A database for storing details or records of every email and phone call made in the UK would be huge, and on a scale I imagine no other database currently has - I would imagine this would be unrealistic? As to infringement of liberties, this would depend on what the database could be accessed for and by whom, but given the record of government IT projects the costs would be prohibitive compared to any benefit I would imagine. Would it not also be duplication as phone companies already keep records of phone calls?
The DNA database would be much more easily managed and have huge benefits for crime detection and is something I would/could support.
Now running for cover from civil libertarians!