Media playback is unsupported on your device Media caption Friday 13th: Why is it unlucky?

It's Friday 13th - allegedly the most cursed day of the calendar and when everything is fated to go wrong. But where did we get the idea that it's a date when bad things happen?

Walking through Birmingham city centre, everyone I ask has heard the myth that dark forces are at work on this "dreaded day".

But do they really believe it?

Do you think Friday 13th is unlucky?

Image caption John and Gillie Hemmer say they have "no qualms" about Friday 13th

Sitting on a bench in Victoria Square are John and Gillie Hemmer who say they have "no qualms" about the date.

"My mum was actually born on Friday 13th," says Mrs Hemmer. "She always thought it was a lucky day - and so do I."

Sitting nearby is Niall Johnstone, who thinks the whole idea is a joke.

"It was put there as something else to worry about," says the 26-year-old. "It's Friday - you've got to love a Friday."

Image caption Niall Johnstone thinks every Friday is something to celebrate

Not everyone is so relaxed about it. In the shadow of the cathedral I find a woman who does believe, even though her sceptical companions cast their doubts.

"It's just a feeling," says Aurora Marin, from Romania.

But where does the myth come from?

The double whammy of Friday 13th

Image copyright Getty Images Image caption The belief that Fridays were unlucky stems from it being the day of the crucifixion, according to one expert

Friday and the number 13 have always been unlucky in their own right, says Steve Roud, author of The Penguin Guide to the Superstitions of Britain and Ireland.

"Because Friday was the day of the crucifixion, Fridays were always regarded as a day of penance and abstinence.

"This religious belief spilled over into a general dislike of starting anything - or doing anything important - on a Friday."

To further compound the chance of peril, an urban legend started circulating sometime in the 1690s that it was unlucky to have 13 people around a table or in a group, he explains.

Folklorist Anne Marie Lagram - herself a "strong believer" - says theories behind "unlucky 13" include the number of people present at the Last Supper or the number of witches to make a coven.

But it was the Victorians who put the two together, says the author of the Country Wisdom and Folklore Diary.

"They were intrigued by folklore and put Friday and 13 together and created a doubly unlucky day."

Where do superstitions come from?

Image caption Georgian Diaconu and Alina Gheorghita are not superstitious but Aurora Marin says she is

There are numerous well-known superstitions, involving black cats, ladders and cracks in the pavement. But where does the sense of foreboding come from?

"Superstition comes from a time when life was uncertain and you felt you didn't have control," says Mr Roud.

"There became a notion of fate as being something you could control by doing lucky things or avoiding doing unlucky things."

For example, Ms Marin - ever the cautious - makes sure to complete a ritual if she sees a black cat.

"If I see one I go back three steps."

Image copyright Getty Images Image caption A black cat crossing your path can be lucky or unlucky according to superstition

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Many superstitions are to do with the idea of upsetting the order of the world, says Mr Roud.

"Opening umbrellas indoors is unlucky and a spade or a wild bird in the house means death. It's the same with shoes on the table - they belong on the floor."

Some stay in our minds as they have become part of our language, he adds.

"Although I count myself as the least superstitious man in the country, I say 'fingers crossed' and 'touch wood'."

And why do they persist?

Image copyright Getty Images Image caption The idea that it is bad luck to put shoes on a table is down to objects being out of place and upsetting the order of the world

Superstitions are learned from other people and persist because they are as good as any other strategy in situations beyond our control, says Michael Aitkin, psychology lecturer at Kings College London.

"Whatever action an individual is doing just before they experience something rewarding might become a superstitious behaviour, which is later repeated even if it is unrelated to the reward," he says.

These personal superstitions are common among people who have dangerous jobs or those that leave a lot to chance, says Mr Roud. Indeed, some footballers are slaves to ridiculous rituals.

Mrs Hemming says once a lucky or unlucky notion gets into your head it is "very hard to un-know it" and more of an effort to avoid it than go along with it.

"If you know it's unlucky to walk on the cracks in the pavement and you've got an important interview that day you wouldn't take a chance on it," she says.

Would you take your chances?

Image caption Joan Carthy and Paulette Hall say they think Friday 13th is "just another day"

Joan Carthy and Paulette Hall are sitting on a windowsill in Birmingham city centre waiting to go to work.

"The only one I won't do is walk under ladders," says Ms Carthy. "It's common sense, there's always something going to fall on you. And knowing my luck it'd be a house brick."

"I've never had bad luck on Friday 13th," says Ms Hall. "It's just another day," Ms Carthy replies.

Mrs Lagram errs on the side of caution.

"I always feel a bit wary when I'm out and about and will send a message to my daughter to be doubly careful on that day."

Couldn't hurt, could it?

This story was inspired by questions sent in by readers and a version was first published in 2017.