The report, on behalf of online pension provider PensionBee, reckons that at least 4.8m pension pots are considered ‘lost’ in the UK.

Meanwhile nearly one in 10 adults believe they could have lost a pension pot worth more than £10,000.

With the total number of UK pension pots expected to soar 130% by 2050 (from 105.8m at present to 243m), the number of lost pensions could skyrocket, the report warns.

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The huge growth in the number of pension pots is partly down to younger workers changing jobs more often, but also as a result of the ongoing impact of auto-enrolment, according to the report.

Today’s youngest workers (age 18) are set to accumulate, on average, five pension pots by the age of 68, but some people could accumulate 20 or even 30 separate pensions over a working lifetime.

As the number of pots amassed increases, so does the likelihood of losing track of them, the report concludes. The research found smaller pots (13%) are more prone to being misplaced compared to larger ones (9%).

Christopher Breen, CEBR head of economic insight, said: "Younger people are moving jobs more frequently than was the case for previous generations. While people tend to switch employers less frequently as they get older, this will still lead to a higher number of pensions being accrued. This is before accounting for the role of AE.

"Given this trend, it's important that the government provides the necessary support and guidance for people to manage their pensions efficiently. With a rapidly aging population, a healthy private pension system is vital for the long-term sustainability of public finances."

Becky O'Connor, PensionBee director of public affairs, said: "The amount of money lost track of in old pensions is already eye-watering, with more than £50bn already at risk of being left behind but is set to reach national crisis levels over the coming years, as the number of pots accumulated through work rises and with it, the number of lost pensions.”