In fact independent research by the Pensions Policy Institute produced a couple of years ago on precisely this issue found that at no point was the change costing £5bn a year, and that the cost to pension funds might be falling each year.
This figure included savings from not granting tax relief to other investors, such as some individuals and charities. The cost to pension funds was lower, at £3.5 billion per year.
The actual cost could be even lower than £3.5 billion because the lower corporation tax rates give companies who make profits more scope to increase their pension contributions, without being worse off. A recent estimate is that the offsetting gain to pension schemes could be as much as £1 billion per year. This means the cost could be as low as £2.5 billion.
The PPI concluded:
[I]t is clear that when the reforms were introduced in 1997 they cost pension funds significantly less than £5 billion per year. It also seems likely that this cost will have reduced over time.
So independent research undermines the £5bn-a-year figure, but has this been accepted by the media? Hardly, in fact the Telegraph claimed last year that the costs to pension funds had been in execess of £100bn. This is based on independent research by an actuary called Terry Arthur. A quick Google reveals that he helped co-wrote a consultation response for the Adam Smith Institute, is a fellow of the Institute of Economic Affairs and contributes to the website of the Libertarian Alliance.
But the Telegraph piece also quotes pensions experts in defence of the figures and the impact of the 1997 tax changes.
While controversial, Mr Arthur's calculations are supported by Stephen Yeo, a senior consultant at Watson Wyatt, one of the most prestigious firms of actuaries.
Mr Yeo said: "This ACT tax change was clearly very unhelpful to pension funds. In terms of its likely long-term effect, £100 billion is certainly a reasonable number."
Stephen Yeo is quite open about the fact that he is a former pensions policy adviser to the Conservative Party. The Telegraph also includes a positive quote from some bloke called George Osborne who I am told may have Conservative connections too.
My point is not that people like Terry Arthur shouldn't be able to air their views. Of course they should. But shouldn't national newspapers be clear about the political affiliations making political points? Equally why is an apparently unsubstantiated figure - £5bn a year - repeated without question by the financial press when a figure backed by indepedent research is available?