"They" want everyone's dna on the database. And police have said that there's no reason to take a person's DNA off the database.
Your DNA is taken and added to the database if you're arrested. You don't have to accept a caution; nor be tried, nor convicted, of a crime for them to keep it. Some people can apply to have it taken off, but it stays on their for two years for everyone.
With the current climate I can easily see "all immigrants need to go on the database" being populist bit of legislation.
[1] typing that name, about my country, feels weird and wrong.
With a database of all communications you have to mine it for probabilistic leads. The signal to noise problem grows as does the database.
Someone else (I cant recall who) said - the last thing you need when looking for a needle in a haystack is more hay.
So the specific deathcount increase is once 5% of the population has access to everyone's data, 1 in 20 abusers will have access to their victims data, to help track down and kill or otherwise continue to abuse.
Likewise it'll be a profitable source of blackmail data.
The recent phone hacking scandal proved that there's few lengths some papers will go to in search of a juicy story.
I wonder how much they'd have to give to some disenfranchised ISP employee to get a couple of years worth of [insert famous name]'s browsing history.
Developers with wide access to data had to be positively vetted to TS level.
A few years ago there was a contract killer that suborned BT employees to find the address of some one in the witness protection schemes parents new address and killed them. The people concerned are doing 10-20 years for conspiracy.
This was the standard Billing Data not the secret squrel side of the biz.