Taken from the Identity Cards Act 2006

Without your consent, your registered information can be given to the following people:

Section 17

The Director General of the Security Service (MI5)
The Chief of the Secret Intelligence Service (MI6)
The Director of the Government Communications Headquarters (GCHQ)
The Director General of the Serious Organised Crime Agency (SOCA)
Chief officers of Police
Commissioners for Her Majesty's Revenue and Customs
Prescribed government departments
Prescribed Northern Ireland departments

Section 18

Anyone the Home Secretary chooses, so long as it's provided for the prevention and detection of crime.

Section 19

Anyone who makes a verification request to the Home Secretary or a Document Authority, in order to correct errors that have been made by the requestor, in the opinion of the Home Secretary's or Document Authority.

(so if you're authorised to make such requests, you can submit an incorrect request and have it corrected for you to fill in any details you might be missing).

Section 20

Anyone the Home Secretary likes, so long as it's in the public interest, and both houses of Parliament agree that's the case.

Section 21

The Home Secretary can also make up new rules for giving information about you to other people without your consent, as long as both houses of Parliament approve them.