In 2014/15, 18 per cent of savers used their full ISA allowance, but that rose to 21 per cent in 2015/16, according to Nationwide Savings.

The survey of 2,000 UK ISA savers also uncovered that men, on average, were “far more likely to take full advantage” of their ISA allowance than women.

Confusion was also uncovered by the study, with people saying they were in the dark about ISA flexibility.

More than three in five (61 per cent) ISA savers admitted they were unaware of the new rules, which allow savers to withdraw from an ISA and replace it within the same tax year, without impacting their annual ISA allowance (2016/17: £15,240).

However, the survey also found that, despite an initial lack of awareness of the ISA flexibility rules, nearly a third (32 per cent) said they would be more likely to use an ISA as a result.

The research also uncovered a difference between men and women when it came to knowledge of the new rules. Some 46 per cent of women were unaware of the new rules compared to just 32 per cent of men.

Tom Riley, Nationwide’s head of savings, said: “ISAs remain an option savers should consider in the new world of the Personal Savings Allowance and it’s good to see from these new figures that not only are ISAs front of mind, but also that many savers are making the most of their annual ISA allowance.

“We welcomed ISA flexibility when it was announced and that is why we moved to ensure that not only did we offer our ISA savers flexibility, we did so at the earliest possible opportunity.

“While we are encouraged that nearly a third of savers are more likely to use an ISA as a result of the new flexibility, it’s a shame that so many people remain unaware of the new rules. As a mutual, we always try to educate our members about things that can potentially benefit them and will therefore keep a focus on this particular issue.”