BRITAIN’S biggest companies face a £40 billion pensions hit this year under new accounting rules that could trigger sharp falls in share prices and force widespread restructuring, new analysis has shown.

FTSE 100 companies with final salary pension schemes have a combined pensions deficit of £50 billion under accounting standards brought in this year. However, less than £10 billion is currently booked in the accounts. There are fears that share prices could be hit when City analysts become aware of the extent of the gap.

The funding gap is disclosed in new research by Deloitte, the accountancy firm. BT, the telecoms group, will change from having a pensions accounting asset of £1.1 billion on its balance sheet to an accounting liability — or provision — of £5.1 billion.

BAE Systems, the defence contractor, will swing from a pensions asset of £400,000 on its balance sheet to a provision of £3.1 billion, based on the company’s last disclosure in December.

David Robbins, a consulting director for Deloitte, said that the full impact of the adjustment could come as a shock to financial analysts. He said: “We were very surprised to find that very little of the pensions deficit is actually in the accounts. Getting from £10 billion to £50 billion in one year is going to be a real jolt.”

Changes affecting quoted companies are required under IAS19, the new international accounting standard for pensions. The impact will start to be seen from July.

Private companies must adopt the comparable UK standard, FRS17, under which pension deficit or surpluses must be on the balance sheet. Across quoted and unquoted companies, the hit in shifting deficits on to the balance sheet could total £100 billion.

Times Recommends

• How to sell your home in a downturn
• How to boost your spending power
• Unemployment benefits explained