The Retail Prices Index (RPI) fell to -1.2 per cent in April and is set to plummet further in the coming months, but inflation still poses a threat to pensioners.

According to Hargreaves Lansdown, state pensions appear fine on the surface. In April the basic state pension rose from £90.70 a week to £95.25, a five per cent increase. Next April it will be reset using the RPI figure from this September, but the minimum annual increase is guaranteed to be 2.5 per cent come what may.

However pensioner inflation runs much higher than average inflation; while the February RPI figure was 0, pensioner inflation in the same month was 4.9 per cent.

As a result,  those prudent investors who have taken out inflation-linked annuities could find their income falling because it is linked to the headline RPI rate.

Some annuity products from Prudential and Standard Life will fall, while those from Norwich Union, L&G and AXA will not (AXA in fact changed their policy in anticipation of deflation).

Laith Khalaf, pensions analyst at Hargreaves Lansdown, says, ‘Pensioners suffer higher inflation than the general population, yet in many cases their income will remain static because it is linked to the headline RPI figure.

‘Despite today’s negative figure, inflation remains a significant threat to pensioners in the long term and those who are about to retire should still give serious thought to how to protect against the erosion of their purchasing power.’

Looking ahead, Khalaf points out that ‘with the possibility of high inflation looming on the horizon as a result of the Bank of England’s quantitative easing programme, retiring investors should inflation-proof some of their pension income. Where possible, splitting their pension three ways between a level annuity, a three per cent escalating annuity and an RPI linked annuity is one solution. Drawdown is an alternative for those with larger pots.’