It's reported that:
The UK's Pension Protection Fund faced a total shortfall of £80.1bn ($153bn) at the end of July from pension schemes in deficit, up from £63.1bn a month earlier and more than double the deficit in July 2007.
And whilst we continue to invest pension funds in high risk assets and base pension returns solely on gilt yields this risk will remain.
The reality is that the only way we can pay for pensions is for this generation to create assets that the next generation actually want, and will pay for. That is the inter-generational transfer that is implicit in the deal. Ignore that and the model can never work. But that's what we are doing.
It's a little dated now (but not by much) but I'll offer the work I did with Alan Simpson MP and Colin Hines called People's Pensions as a much better solution.