Did Gordon Brown's "stealth tax" raid on pension funds cause the spectacular decline of final salary pension schemes? Absolutely not. Did it do damage? Indubitably - and quite a lot.
But was it even the main cause of two-thirds of defined benefit schemes now being closed to new members? No.
That was the conclusion yesterday of Stephen Yeo, a senior partner at Watson Wyatt, the pension consultants. As a former adviser to David Willetts when he was the Conservative pension spokesman, Mr Yeo is no apologist for the chancellor.
But he declared: "I don't think it is even in the top three reasons" - while acknowledging that "it certainly wasn't helpful".
Three key factors undermined defined benefitpensions.
First, what were once aspirations were turned by successive governments into guarantees that employers had to meet. One example was a promise to protect against inflation both the rights of employees who had left for other companies, and those whose pensions were already being paid out. Lord Turner estimated these changes increased the cost of pension provision by about 50 per cent.
Second, increased longevity hugely raised costs: a 65-year-old man is now on average expected to live for 20 years, against 12 in 1950.
And third, the long bull market of the 1980s and 1990s, which had made pensions appear almost cost-free, ended. The collapse of the dotcom boom in 2000 wiped around £250bn off pension fund assets.
Add to that accounting rules that put pension deficits on the balance sheet just as they were ballooning, and the existing drift towards closure of final salary schemes became a stampede.
The contribution of the tax credit change to this was not insignificant: a £50bn hit against a £250bn stock market fall, and far greater longer-term costs from rising life expectancy and inflation proofing.
Elsewhere both the TUC and NAPF have put out statements arguing that abolishing tax credits did not cause the crisis. Perhaps they could tell Jeff Randall.