Volunteers were challenged to track down key pieces of information about their pension schemes to see what problems they faced.

Nine of the 12 volunteers saw gaps in their data, while only three were able to find all the requested information via paper statements, online accounts and phone calls.

Some savers struggled to find the value of their pension or projected entitlement under a defined benefit scheme. In another case, the saver was told they would need to wait 40 working days for a new statement with the information.

The investigation by campaign group Which? revealed several volunteers discovered errors and missing information, notably around pension charges and investment strategy.

And in cases where the information was available, it wasn’t always correct.

One of the participants – a 36-year-old from London – found that pension payments had been deducted from her salary but over eight months, the contributions failed to be added to her account, potentially breaking the law.

Some volunteers said they were left confused following pension company mergers and takeovers, with one volunteer receiving three letters from different providers about the same scheme.

Which? is calling for the urgent introduction of a comprehensive pensions dashboard so savers can see all their pensions in one place, helping them track and better understand their retirement pots.

The pensions dashboard project was first announced in the 2016 Budget and the government originally promised to ensure that it was designed, funded and launched by 2019. But a prototype version probably won’t be available until 2021 at the earliest.

Gareth Shaw, head of money at Which?, said: “A pensions dashboard could be a game changer for consumers who have struggled for too long with a complex, fragmented pensions system.

“For the millions of pension savers to get genuine benefit from a dashboard, the government must use this opportunity to ensure it delivers all the information consumers need to see including charges, income projection figures and state pension entitlement.”