Hello Ted,
iShares has very good reporting of what the underlying index is, and provides full details on their site. In this instance it tracks the Barclays Capital UK Government Inflation-Linked Bond Index.
Below is the link that will take you to their page all about it. If you click the 'holdings' tab, that's where you'll find the detail.
http://uk.ishares.com/en/pc/funds/INXG I would suggest being mindful of any rolling charges that your platform or online broker may impose, in addition to the annual costs from the provider, as some treat them as shares and this could be as much as £50 a year.
Good luck,
Frank