Jerry Barnfield, Norwich Union's director of pensions, said: 'Until now, we have suggested men aged 54 and women aged 48 should consider going back into Serps because there is not enough time for their pension to grow on the stock market. However, lots more people will now be better off with the State system. The risk of opting out is getting bigger because you are giving up a guaranteed State benefit for a stock market investment which is not guaranteed.'