Already exists illegally
This mega database ALREADY EXISTS. The Snoopers Charter debates brought this to peoples attention, and now she feels the need to try to legalize it. It was revealed last year (link below). It has no legal basis, and pisses all over the privacy right and database laws. Hence she's now trying to retro-fit UK law to make it legal.
What they did was seized data within the law (mostly RIPA the joke of a law), stick it into a big database. Then when they want to go fishing they don't follow the legal process with its checks and balances and instead search their own private copy.
Snoopers Charter, in theory it is a filter on Internet data to investigate crime. In reality it is a data-feed into this database. The filters are broad (unspecified) and intended to populate this database. The police search their local copy, free from judicial process, and oversight, and any consequences for misuse.
Due process? Nope. Right to judicial process? Nope. Right to privacy? No, there are watchers and watched. The watchers control the watched, but in turn have zero oversight over them.
Right to democracy? Nope, because the voter was kept out of this, they voted in Cameron and May without knowing what they knew.
Of course all that's going to happen is mafia police.
At this point, nobody in Parliament can list WHO gets WHAT data from WHERE under what LAW. Because they're not following the laws. They're doing whatever they want, and their bad-actors in Government (which their surveillance helps put in place) then try to make legal whatever they're doing.
I bet May's Government can't list the data-feeds either. I bet you couldn't get Theresa May under oath to Parliament to enumerate even a fraction of the list. Parliament can pass all the laws, and courts can interpret those laws, but this lawlessness of Police and GCHQ means thats meaningless chatter.
"The Agencies use Bulk Personal Datasets -- large databases containing personal information about a wide range of people -- to identify individuals in the course of investigations, to establish links, and as a means of verifying information obtained through other sources. These datasets are an increasingly important investigative tool for the Agencies....
"Until the publication of this Report, the capability was not publicly acknowledged, and there had been no public or Parliamentary consideration of the related privacy considerations and safeguards.
"The legislation does not set out any restrictions on the acquisition, storage, retention, sharing and destruction of Bulk Personal Datasets, and no legal penalties exist for misuse of this information.
"Access to the datasets -- which may include significant quantities of personal information about British citizens -- is authorised internally within the Agencies without Ministerial approval."