Shares in Aviva, the owner of Norwich Union, were among the top performers in the FTSE 100 index today after the group insisted its capital solvency was strong and revealed overall growth in sales because of a strong performance in the US.

London's leading shares neared the 4000 barrier before closing 73.8 points higher at 3926.4 - a gain of 2 per cent and the first positive session since Thursday.

Aviva's stock rose 16.21 per cent at lunchtime, closing up 5.61 per cent 259p. After an initial rally, its rival, Old Mutual, ended the day down by 8.24 per cent to 39p.

The market was also encouraged by a bounce back in the Japanese and Hong Kong stock markets, which helped mining stocks to recover.

While overall sales rose in the nine months to September 30, Aviva gave warning that revenue would slow for the remainder of this year as financial turmoil continued around the world.

Andrew Moss, chief executive of Aviva, said: "Our share price has been affected by the huge uncertainty in financial markets, but people around the world are still saving and buying insurance.

"Investors and customers can be confident that our disclosures provide a full picture of Aviva's financial position."

There have been mounting concerns that corporate bond defaults will weaken Aviva's portfolio.

The company said its regulatory buffer has fallen from £1.9 billion at the end of September to £1.3 billion when last calculated last Friday.

It would fall to £900 million if the FTSE 100 fell another 20 per cent.

Life and pension sales in the nine months to September 30 increased by 12 per cent as a slight fall in the UK was made up for with growth in the US, Poland and the Netherlands. However, total investment sales fell 37 per cent as falling equity markets put people off investment products.

Mr Moss warned that the £1 billion due to be paid to with-profits policy holders under a deal with the Government over the use of its "inherited estate" may be cut, given the falls in the stock market.

"The FTSE stood at 5,421 on July 30 this year, the day our offer was announced," he said. In making the £1 billion offer "we made assumptions about the value of the estate, which have naturally been affected by market conditions."

Times Recommends

• Minister in talks with Saudis to protect creditors
• Premier Inn hits back in £29-a-room row
• Bankers hit back at 'populist' bonus supertax