Obviously (tm), it's the risk that the data will be used against us by those OTHER than the gov't, that is the problem.

'He said that there was an “inherent fear” of the data falling into the wrong hands and being used against people.'

The WHOLE POINT of establishing the database is to use it against us, remember?

Then with a decent level of public protection we can start listening to how they will guard our very valuable and private data.

Of course GCHQ doesn't want the government doing the database thing. All it does is alert the population about monitoring and will result in it being far more difficult for the spooks to hoover up all the publicly available information...