The relevant section is this:
See the following sections:
Section 12 Notification of changes affecting accuracy of Register
(1) An individual to whom an ID card has been issued must notify the Secretary of State about-
(a) every prescribed change of circumstances affecting the information recorded about him in the Register; and
(4) The things that an individual may be required to do under subsection (3) are-
(a) to attend at a specified place and time;
(b) to allow his fingerprints, and other biometric information about himself, to be taken and recorded;
(c) to allow himself to be photographed;
(6) An individual who contravenes a requirement imposed on him by or under this section shall be liable to a civil penalty not exceeding £1,000.
From Section 1
(6) In this section references to an individual's identity are references to-
(a) his full name;
(b) other names by which he is or has previously been known;
(c) his gender;
(d) his date and place of birth and, if he has died, the date of his death; and
(e) physical characteristics of his that are capable of being used for identifying him.
So, the system could be brought to a shuddering halt by lots of people writing 'Dear Mr. Secretary of State, under sections 1 and 12 of the ID card legislation, I am writing to inform you that I have had a shave this morning.
Of course, as the legislation refers to 'him' women dying their hair aren't covered by the legislation.
Unless they're classed as male for the purposes of this law.
Dear Mr. Secretary of State. I have cut my finger, thus rendering this biometric temporarily out of date. Under sections 1 and 12 of the ID card legislation I am writing to inform you of this. As I wish to comply with the law, however idiotic, I wonder if you could please make an appointment for me at the nearest processing centre.
... and so on.
I am pleased to report that my MP voted 'No'. The previous MP, whose name is still at the top of the report, couldn't be arsed to even show up for the previous four votes on this issue, so we have progress.