Two new reports published this week show the finances of the UK's pension plans to be worsening, despite 2009 being the best year for investment returns since 2005, but behind the alarming headline figures lies a strong contributing factor that could be up for reconsideration.

The consultancy Mercer, which advises companies on their pension plans, said today that the combined shortfall on the country's 350 biggest schemes was £170bn (€189bn) at the end of last year, a staggering increase on the £60bn deficit at the end of 2008.