A report by the Pensions Policy Institute argues that the present system makes the assumption that contributors pay into their pension fund throughout their working life and earn good incomes.

As a result, those with varied working life patterns can find themselves “under-pensioned”, the study explains.

The PPI claims that recent reforms to UK state pensions do not go far enough to help many Britons and insists that the state pension should be reformed so it is fair to all groups in society.

The report also points out that the recently introduced State Second Pension and Pension Credit will not fully compensate under-pensioned groups.

The PPI recommends a number of possible options, such as scrapping the second pension and increasing the basic state pension, or introducing a citizen’s pension, with payments according to residency rather than the levels of contributions made.

“The structure of the UK pension system means that any group with low earnings or an irregular employment record will lose out in retirement,” said report author Chris Curry.

“The system disadvantages groups such as women, ethnic minorities and disabled people, who are more likely to work part time and have low earnings.”