According to the report, carried out by Ernst & Young on behalf of MetLife, just two per cent annual inflation reduces spending power by 40 per cent over 25 years and, if inflation hits five per cent over the same period, spending power is cut by 70 per cent.

However, the report also predicts that the twin challenges of increased longevity and long-term economic factors will mean ‘big opportunities for providers and advisers’ if the financial services industry grasps the chance to provide new solutions.

Current low rates for traditional annuities are unlikely to ‘improve substantially in the foreseeable future’ and many drawdown products offer no protection against investments falling.

Ernst & Young’s Malcolm Kerr says, ‘Changing attitudes to retirement create substantial opportunities for providers and advisers but ,at the same time, create threats. With high expectations of retirement there is a clear risk of disappointment should retirees’ pension provision prove inadequate.

‘Financial planning and product solutions will need to support the aspirations of retirees while also addressing their key concerns. An intelligent, successful and more confident generation of affluent retirees is beginning to emerge – clear on their priorities and preferences.’

The research suggests that someone earning £35,000 a year will need a pension fund of around £300,000 in order to guarantee an income of £20,000 on retirement.

And the introduction of personal accounts under the National Pension Savings Scheme could deter consumers from saving while encouraging employers to 'dumb down' their pension schemes.

The report argues that the changes in occupational pension provision from defined benefit to defined contribution schemes means the investment and longevity risks are being switched to individuals.

It identifies the advantages of unit-linked guarantees as enabling investors to access increasing income, if required, with the potential to benefit from stock market returns.

Dominic Grinstead, strategic development and marketing director at MetLife, says, ‘The retirement planning market has a strong record of innovation but, clearly, more needs to be done.

‘Our own experience shows that advisers are well aware of the issues and are keen to identify more solutions for investors. MetLife believes that products such as unit-linked investments offering guarantees can play an important part in the changing the retirement market.’