One-third of UK adults would not be able to cope with an unexpected financial shock or loss of income, while nearly a quarter have no savings to fall back on at all.
That is according to research from Zurich UK, which estimates that there are around 17.6 million financially vulnerable people living in Britain today.
It was also found that one in ten Brits have no idea what impact a financial shock would have on their income, and that a quarter to do not feel in control of their lives.
With Brexit on the horizon, Zurich UK head of strategic partnerships, Rose St Louis, said the "worrying" findings highlight the need for people to seek greater financial support.
"The most valuable asset we have is ourselves and our ability to generate an income," she continued. "We need to encourage people to consider what support exists.
"Products like an income protection plan - designed to provide a regular income if you are unable to work - could help individuals feel less vulnerable and more financially resilient."
Despite this suggestion, it was found that just 11% of Brits have such a plan, far less than the 71% with home insurance, and even fewer than the 18% that get coverage for their mobile phone.
Neuroscientist, Dr Jack Lewis, said the reasons for more people insuring their house or mobile was down to psychological phenomenon known as the 'availability heuristic'.
This is when people feel a stronger perception of risk from threats they commonly observe in everyday life, even if they might not be as damaging.
"By comparison, I cannot think of a single occasion when I heard someone explaining what a lifeline their income protection was when they lost their job," Lewis said.
The research also found that a third of UK adults believe they would need to be earning £1,000-£2,000 a month to feel financially resilient, rising to £2,000-£4,000 for a fifth.
"We need to educate people and help them to understand that there's support out there - there are products to ease the stress and worry of a financial shock and loss of income," Lewis added.