More than five million people lost their keys last year - with women the worst offenders, according to a study.

The research for card protection service Sentinel showed 5,626,356 lost their keys, with one in 10 people losing them up to three times.

But it found one in every 50 women claimed they lost keys five times or more, although no men admitted losing them more than three times.

The research, commissioned for the launch of the company's new lock and key protection service, also found many people underestimated the cost of replacing sets of keys.

And worryingly, it finds more than half (53%) keep keys with some form of identification, with women again worse than men, as 60% keep keys with personal information.

Psychologist Corinne Sweet said losing keys was indicative of how stressed people were: "Losing keys is a distressing experience for most people who are juggling impossibly busy home, work and family lives today.

Parapraxis

"However, the loss of keys also reveals how stressed people really are deep-down, as it is a typical psychological "parapraxis", or Freudian slip.

"Thus, the more hectic your 24/7 daily life, the more likely you will become absent-minded because of psychological overload - which ends up with you losing your keys."

Matt Simester, Sentinel's development director, said: "It is also troubling that such a high proportion of people, particularly women, are keeping their keys with personal information.

"Not only does this put you and your property at risk, it also leaves people vulnerable to identity theft, one of the fastest growing crimes in the UK."