The firm questioned over 1,000 people for the survey which has been running quarterly since 2004.

People who were confident in their finances saved £104.39 per month compared to the £53.47 saved by worriers.

Over a year, this adds up to over £1,000 saved compared to £636. NS&I said 41 per cent of worriers spent more time worrying about finances and doing something about it.

This lack of action means 25 per cent of people feel guilty when they overspend due to planning failures.

John Prout, spokesman at NS&I, said: “Britons seem to be getting into a cycle of financial fret. Time is spent worrying instead of focusing on money management and finances suffer as a result, causing more stress.”

However, the smaller proportion of people who were planning their finances often also found ways to make their money go further.

Some 23 per cent monitored different savings accounts, another 23 per cent had a direct debit from their current account to savings account and 17 per cent set a daily expenditure diary.

Sue Whitbread, communications director at the Institute of Financial Planning, said: “This is a huge problem, and something we’re well aware of. The consumer surveys we’ve carried out for Financial Planning Week over the past four years consistently show that people are worrying about their finances yet do little to improve their situation by making proper financial plans.

“In conjunction with Accredited Financial Planning Firms we’re working on a campaign over the summer to raise awareness of the benefits of Financial Planning directly with consumers. We’ll also be running the fifth UK Financial Planning Week initiative from 26 November where we aim to help people to take some simple steps themselves to improve their financial fitness.”