The flu jab blunder which contributed to the largest spike in deaths in a generation may have brought unexpected benefits for Britain’s pension black hole, a new report suggests.

Latest projections from the The Institute and Faculty of Actuaries (IFoA) show that the increase in the mortality rate in 2016 has slightly reduced overall life expectancy for the over 65s, down 1.3 per cent for men, and 2 per cent for women.

According to Mercer, the world’s largest human resources consulting firm, the shift has removed around £28 billion of pension scheme liabilities from the balance sheets of FTSE350 companies.

Last year figures from the Office for National Statistics (ONS) found there were 16,415 excess deaths in the 2015/2016 winter, the largest percentage increase since 1968, with flu blamed for the large increase.

The extra deaths were fuelled by the flu jab being mismatched for the main strain of influenza, which unexpectedly mutated, meaning it worked for just one in three adults, compared to the 50 per cent it usually protects.