Unfunded public sector pensions

While tracking down the source of a quote for my previous post, I stumbled across this in Hansard (Column 20/21) from back in 1993:

Mr. David Shaw (Dover) : ... I asked a specific question about the cost over the next 20 years of the commitment to public sector pensions for civil servants and others. I have been told that the unfunded liability, which does not appear anywhere in Government accounts, is £170 billion...

And they thought they had it bad! Meanwhile the liability is six times that and rising.