More than 1.7 million Brits are at risk of online fraud as they use the same password for every site they use.
Nearly half (46 per cent) of Brits use the same password for places they need to login to, such as online banking and shopping websites, as well as social networks, according to the research conducted by card insurer CPP.
This is a similar finding to research released earlier in the week by PC Tools, which said that nearly half of men and around of quarter of women used the same password for all their sites.
A fraudster finding out a user's password would have access to an average of 23 sites because of this one password approach, according to the research.
Nearly 40 per cent of adults admitted that at least one other person knew their passwords, such as colleagues and friends, with over a third of these people believing that they may have logged in using their details.
Most of the Brits surveyed (68 per cent) claimed that it was too difficult to remember logins, while 17 per cent said they were worried about forgetting a password and being logged out.
"No sensible person should use the same key for their house, car and garage," said CPP identity theft expert Sarah Blaney in a statement. "In the same way, we shouldn't use the same password for everything."
"If possible, people should use multiple passwords with a combination of letters and numbers, which should be difficult to crack."
One in 10 people already had web accounts accessed, with 57 per cent of attacks happening in the last year. One in 20 reported having their ID stolen.
Around one fifth of the hacked Brits had goods illegally bought in their name, with one in eight having money stolen, the average lost being over 1,000.
