Over 20 million Britons believe they could survive for up to six months on ‘emergency' funds despite half having less than £1,000 available in accessible savings.
According to Bright Grey's Financial Safety Net report, the figure is five times worse than two years ago with women being particularly vulnerable.
It also found that the ownership of protection insurance had dipped in spite of increasing debt burdens for many.
The insurer's research with 2016 Brits found that 41% of adults would only be able to rely on savings, borrow from friends and family or rely on credit, for up to six months in a financial emergency.
In 2010, this figure was a quarter of that, meaning four million adults would run out of money after six months.
Half (49%) of those surveyed believed they could rely on these types of support to survive financially for over a year.
Yet despite this, and the fact that more adults are getting into debt, the number with a financial protection product in place is also falling.
Three in five (60%) have no cover whatsoever compared to 58% a year ago - whether that's life insurance, critical illness or income protection.
A typical adult in 2012 thinks they can use savings, loans or financial help from friends and family for an average of 290 days, a decrease of around one month from a year ago.
The study also showed that nearly half (43%) of respondents say they have £1,000 or less in savings that they could access immediately.
Indeed, nearly a quarter (23%) have no money saved at all.
The gender gap is still very much in evidence, with 45% of women having £1,000 or less in savings compared to 38% of men.
Should the main breadwinner be diagnosed with a serious illness, suffer a disability or die, one in four (24%) adults said that they would need to cut back drastically on their living costs while (24%) said that they would not know what to do in this eventuality.
And one in ten (11%) said that they would have to sell their house.
Roger Edwards, proposition director at Bright Grey, believes the results illustrate how little attention Britons pay to their personal finances.
"We urge everyone to improve their own personal financial safety net, in preparation for any situation where the main breadwinner finds themselves unable to work," he said.
"Having proper provisions in place means that you and your family can remain financially afloat for years, not months, should you or a loved one become disabled, seriously ill or die.
"It is important for men and women alike to consider their financial futures, as sadly there are many thousands of people who find themselves in a position where they are in urgent need of extra finance.
"With the EU gender directive due to come into force in December, the average cost of womens' protection in particular is set to rise, and people should take advantage of the current rates to ensure long term financial survival," he added.
