John Hemming identifies clauses in the Identity Cards Bill governing the information that must be kept up-to-date on penalty of £1,000 fine:

(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

(e) is probably the most exciting. If the campaign against ID cards fails and they are introduced, perhaps the system could be overwhelmed by thousands of people writing every day to the Secretary of State to update him on changes to their physical characteristics?

Dear Home Secretary,

I’m just writing to let you know that I cut myself shaving this morning and now have a clearly identifying mark on my right cheek.

Yours,
I.D. Card-Holder

or

Dear Home Secretary,

Just thought I should mention that I’m feeling really rough today. I drank too much last night (don’t worry, I wasn’t in an Alcohol Control Zone) and this morning my hair’s a mess, my breath stinks and I’m too hungover to do anything about either. These distinguishing marks may be important should I be today suspected of terrorist involvement.

With love,
I.D. Card-Holder

or

Dear Home Secretary,

Contrary to my letter last week, I have decided to wear contact lenses only on Tuesdays and Thursdays. not Tuesdays, Thursdays and Saturdays as previously notified. I like to go out on a Saturday and I thought the contacts would make me look less speccy but the bars I’ve been frequenting are quite smoky (they don’t serve food, y’see) and the tobacco has been playing havoc with my corneas.

The upshot is that if someone tries to claim benefits in my name on Saturdays, you’ll know it’s not me if they’re not wearing glasses.

Yours sincerely,
I.D. Card-Holder