Prospect has warned in a new You Tube video that the tax raid on pensions made by Labour in 1997 is dwarfed by the current government's decision to link increases in pension benefits to the Consumer Prices Index rather than the Retail Prices Index.

Prospect deputy general secretary Dai Hudd says: "This is by far a bigger raid on pensioners than anything envisaged by the previous government. The Department for Work and Pensions has indicated that the value of accrued pensions will reduce by some £200bn.

"This is a colossal figure and it does represent money taken directly out of the pockets of pensioners now, pensioners in the future and those people accruing benefits currently."

Hudd explains that the legal challenge launched on April 18 by Prospect and five other unions will question the statistical validity of the CPI for uprating pensions, arguing that it is not an ‘appropriate index'.

This issue has already been brought to the fore by, among others, the Royal Statistical Society, which has written to the government saying: "We do not feel that it currently serves the purpose of being a sufficiently good measure of inflation as experienced by households to be used in uprating pensions and benefits or for use in wage negotiations."

You can watch the video here.