One sheet of 7 Passport size photos for 12p.
Edit your own pic on http://www.epassportphoto.com
(courtesy of dwl99)
Take instore, print on 1hr service @ 6x4 inch for higher quality results !
Hope you dont mind me adding this!
Alternatively you can take your photo into store on a memory card or USB stick, and pay the full £1.17.
Guidelines for producing photographs for United Kingdom Passports can be found here: http://www.ips.gov.uk/cps/rde/xchg/ips_live/hs.xsl/36.htm