The RPI/CPI change is currently being challenged in the courts by several unions, including my own.
http://www.professionalpensions.com...feels-heat-cpi-switch-challenge-reaches-court
As well as adding to the petition you should also contact your MP.
http://www.professionalpensions.com...feels-heat-cpi-switch-challenge-reaches-court
As well as adding to the petition you should also contact your MP.