The deficit of the UK’s 6,000 defined benefit (DB) pension funds grew by £100 billion in the last month alone, bringing the total deficit to £710 billion, according to new figures released by PwC’s Skyval Index.

This is based on the value of liabilities used by pension fund trustees to determine company cash contributions.

Raj Mody, partner and PwC’s global head of pensions, said: “With the prospect of further action from the Bank of England to reassure the economy in these uncertain times, the challenging environment for pension funds is likely to endure for several years.

“PwC’s recent pensions risk survey showed that half of funds had not protected themselves against falls in long-term interest rates.

“Companies and pension fund trustees should revisit their approach to the risk profile of their pension fund.

“They should also ask themselves if gilt yield measurements are still relevant for them when deciding how to measure and finance the deficit.

“There may be more appropriate measures that are better tailored to their own fund’s strategy.

“This will give a more realistic view for trustees and sponsors helping them to make more effective decisions.”