Ructions in the debt markets have caused a discrepancy of more than £130bn (€133bn) in attempts to calculate UK pension schemes' bills, causing one actuarial consultant to brand the accounting methods "a black comedy".

The audit firm Deloitte said yesterday that 2008 had been a "terrible year" for the country's pension funds, with the UK's biggest 100 companies losing £65bn from the value of their investments as markets tumbled around the world.