Following Nermal's suggestion, I applied for a new passport as described here:
http://www.renewforfreedom.org/.

Although my passport had nearly 3 years to run, no questions were asked about the reason for renewing early, and the new passport came through in exactly a week, valid until 2017.

A leaflet was enclosed which states:

The Government expects that the new style passport identity cards will become available to all those applying for new and replacement passports from around 2007/8 onwards. Your new passport is unaffected by these developments, and will remain valid for the entire period for which it has been issued, subject to passport rules and current visa requirements.

The wording is interesting: I particularly like "will become available" and "subject to passport rules and current visa requirements".

In other news: rejoice - Charles Clarke has been sacked. See also:
http://disruptive.org.uk/2005/11/02/rejoice!_2.html
http://disruptive.org.uk/2004/12/15/rejoice!.html.

Of course he has been replaced by another "thug in a suit".