This represents a 21% year-on-year increase and a total of £48bn is now saved in defined contribution (DC) schemes.

Nine in 10 people currently saving into a private sector pension are doing so via DC schemes, said the Regulator’s report.

Membership of DC schemes (with 12+ members), which includes those who come under auto-enrolment, has risen to 12.6 million people, up 29% over the past year. Since the start of 2010, the number of people saving into DC schemes has risen 400%.

However, TPR notes that the average asset per membership has fallen from £4,700 in 2016 to £3,900 in 2017.

The number of DC schemes has continued to fall. Since 2010, the number of schemes, not including micro or self-administered schemes, has reduced by 52% from 4,560 to 2,180.

TPR also reveals master trusts account for a major proportion of the increase – 10 million DC savers in total from the 270,000 reported at the start of 2012.

There are 10.5 million members in defined benefit schemes, with a total £1.5bn assets, according to the Pension Protection Fund.

Anthony Raymond, acting executive director for regulatory policy, analysis and advice at TPR, said: “The success of automatic-enrolment has put DC schemes – and particularly master trusts – at the heart of pension saving in the UK, and our figures illustrate this trend.

“For these new and existing savers we have a role to protect their benefits and so we are working hard to drive up standards of trusteeship. We are also implementing the Pension Schemes Act 2017, which requires master trusts to meet a clear set of standards in order to obtain authorisation from us to operate.

“We welcome the continued reduction in numbers of DC schemes. We have been concerned about a tail of sub-standard schemes and have been encouraging trustees who cannot or will not meet the standards we expect to consider consolidation.”