The UK Statistics Authority recently ran a joint consultation with HM Treasury on changes to the Retail Prices Index methodology. The response to that consultation will be published on 25 November, alongside the Spending Review.
An exchange of letters between HM Treasury and the UK Statistics Authority confirming this date is available here:
Chancellor of the Exchequer to Sir David Norgrove – RPI Consultation update
Sir David Norgrove response to Chancellor of the Exchequer – RPI consultation update
Consultation on the Reform to Retail Prices Index (RPI) Methodology