I have been asked to reply.
The rollout strategy for issuing identity cards to foreign nationals is set out in "Introducing compulsory identity cards for foreign nationals", which was published on 6 March 2008. This means, that from November 2008, foreign national students, subject to immigration control, and who apply for leave to remain in the United Kingdom, will be required to apply for an identity card issued under the UK Borders Act 2007. Eventually, all foreign nationals, subject to immigration control, including students with existing leave, will be required to apply for an identity card.
The identity card will provide evidence that the holder has leave to enter or remain in the United Kingdom as a student. Foreign nationals issued with an identity card will be required to produce it when asked to provide evidence that they are entitled to study at an educational institution.