The reports about companies closing their schemes cited the current financial climate and interest rates as well as longevity, as being the reasons.
This is depsite the fact that pension funds are long term investments that will see good economic times and bad, and despite the fact we were implicitly told at briefings that the current downturn had no real bearing on the fund and was not an issue we should focus on.
The current downturn has little or no bearing on the contribution rate to the fund because as you say pension funds are long term investments. However it does have a bearing on any company's ability to pay those contributions and current legislation now makes if very difficult to defer contributions. There will be many companies forced to close their schemes simply because they can't meet the contribution rate set by their trustees. Those industries worse hit by the recession will be those most likely to do this.