The Liberal Democrat home affairs team today renewed their passports, to demonstrate their opposition to ID cards.
The MPs' passports will be valid for ten years, buying them what they called "ten years of freedom" from the national identity database.
From October this year, first time applicants for passports will have to attend an interview, have their fingerprints taken and irises scanned. From 2008 the same will apply to those wanting to renew their passports.
A person's details will be entered into a national identity database, and from 2010 they will be issued with a card that will include a microchip holding biometric information, including their fingerprints, iris or facial scans.
The Conservatives have promised that if they get into government they will repeal the law, and the Lib Dems have opposed ID cards from the beginning, on grounds of civil liberties and expense.
On renewing his passport today, Lib Dem home affairs spokesman Nick Clegg said: "ID cards will be expensive, intrusive and ineffective.
"I urge everyone who is concerned about their introduction to join the NO2ID Renew for Freedom campaign and renew their passport over the coming weeks.
"The Liberal Democrats were the only party to vote against the introduction of identity cards, and we're making our opposition clear today by buying ourselves ten years of freedom from this unnecessary scheme."
The House of Lords rejected the ID card plans five times, eventually settling on a compromise, allowing people not renewing their passports to opt-out of the scheme.
In March this year, former home secretary Charles Clarke confirmed that those who feel "strongly enough" about ID cards would be free in the initial phase of the scheme "to surrender their existing passport and apply for a new passport before the designation order takes effect".
However, the government was keen to point out that the cards would not store details about race, religion, sexuality, health, political beliefs or criminal record.
It argued the scheme was not unlike those in a number of other European countries, and would improve national security, tackle identity fraud and improve border controls.