The independent pensions consultant said current pension options are “not fit for the future” as low risk investments have become more hazardous. She also said retirement was now a “process not an event”.

Her latest paper, Time for Change: Rethinking pensions and retirement, said the auto-enrolment would see millions enrolled into defined contribution schemes which would not future lifestyles.

“There is a real danger of lulling employees into a false sense of security about their retirement incomes because current pension products are designed for the past, rather than the future.”

Altmann, a former Downing Street adviser, said pension funds at present are inflexible and risky.

“Most workers will be put into defined contribution schemes, where the final pension depends on investment returns and annuity rates. The inadequacies of the standard investment options being offered and the scandal of poor value annuities means that the pensions people ultimately receive are likely to disappoint.”

The paper also highlighted the growing discord around annuities being the default option for retirees looking to extract money from their fund.

She said: “Most pension scheme default funds also assume that, on retirement, workers will buy an annuity. Investments are often automatically switched into ‘low risk’ bonds in the run-up to the pre-set ‘retirement’ date, in order to reduce the risk of loss just before retirement and to prepare for annuity purchase.

“This strategy may be wrong on two counts. Firstly, workers may not actually buy an annuity. Secondly, the bonds that are bought may turn out to be more risky than expected.”

Altmann quoted a MetLife survey which found just one in ten financial advisers would buy an annuity at current poor rates.

“The poor value offered by annuities at the moment, partly caused by the suppression of gilt yields resulting from Bank of England gilt-buying, is clearly recognised by financial advisers.

The MetLife survey showed that fewer than one in ten financial advisers would buy an annuity now, even on an impaired life basis. Yet most workers currently believe this is what they have to do with their pension fund and most of the pension funds are geared to annuity purchase.”

She also highlighted figures showing gilt investments had lost about 10% of their value since August 2012. “Hardly safe”, said Altmann.