Image caption Many can't explain their actions

Chef Antony Worrall Thompson has apologised for shoplifting from a supermarket. But what makes people steal things when they have enough money to pay?

Worrall Thompson has apologised for his "stupid and irresponsible actions", after being cautioned by police for leaving a branch of Tesco without paying for small value items. He had reportedly done this on five separate occasions.

The 60-year-old has spoken of the shame of letting his family and friends down. The big question, he says, is "why".

Experts agree that in these cases, shoplifting is rarely about genuinely needing the item that is stolen. It is often about seizing the opportunity to momentarily exercise control when the perception is one of powerlessness.

Research by retail consultants Global Retail Theft Barometer and Checkpoint Systems has suggested a new wave of middle-class shoplifter is targeting high-end delicacies from supermarkets in order to maintain a lifestyle they could no longer afford. These are people who appear to be reputable and often justify their actions by arguing that they have become victims to the economic recession.

But in most cases of stealing by what psychologists describe as "non-professional shoplifters" - those who don't steal for profit or resale, or to feed a drug or alcohol addiction - there is much more going on.

A devastated Worrall Thompson, in an interview with the Daily Express, said that he was unable to comprehend what compelled him to take items such as onions, a sandwich, cheese and wine.

On one occasion I paid £180 for three crates of champagne and at the same time nicked £4 of stuff - how ridiculous and how stupid Antony Worrall Thompson More from his Daily Express interview

"I've been racking my brains to think why on earth did I do it and what was going through my mind at the time," he said.

Experts say this is a typical response from a "non-professional shoplifter".

Shoplifting is generally a reaction to some kind of loss and a need to fill a void - real or perceived, says Barbara Staib of the National Association For Shoplifting Prevention in the US.

"Shoplifters are generally honest citizens," she says, adding that research has revealed a "direct correlation between depression and shoplifting".

She explains that while other people might turn to alcohol, or binge eating, others turn to shoplifting.

"Some people are trying to find solace in shoplifting," she says. "It gives them the 'rush', a 'high' - it can be a relief, if only a temporary one, as they suffer remorse afterward, when they get caught.

"These are people who go into a store and the opportunity arises. For some reason they rationalise, they convince themselves that it's OK - for that moment. This is maladaptive behaviour - a way of coping with things that are going on in those people's lives."

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Worrall Thompson joins a list of people in the public eye who have been accused of shoplifting. A decade ago, American actress Winona Ryder was convicted of stealing thousands of dollars worth of clothes.

In an interview with Vogue magazine a few years later, she blamed her actions on painkillers that she said she had got from a "quack" doctor after breaking her arm a few months earlier.

The painkillers, she said, left her in a state of "confusion".

Canadian psychologist Dr Will Cupchik has spent decades researching and working with what he describes as "atypical theft offenders" - the wealthy, celebrities or those in the public eye. The last thing these people need, he says, is to steal.

"There are many reasons why people who have so much to lose risk so much for so little," he says. "These are people who are reasonably well off and are basically honest.

"This is not typically about risk-taking - it's not done just for the thrill of it."

He believes that the shoplifting episodes are a response to what those people perceive as an experienced or anticipated "unfair, personally meaningful loss".

Image caption Experts say many steal to fill a void in their lives

This might include anything from losing a TV show, to problems with an intimate relationship or a child with an illness, he says.

"[The shoplifting] can be described as a hole that they want to fill - in the same way that people eat too much, drink too much or work too much."

And in many cases, when caught, their behaviour doesn't make sense to them.

"In most cases, timing is important," Cupchik says. "I say to people, 'Tell me what happened in your life either earlier that day or the day before', and it will often be something profound."

He relates the story of a top lawyer who stole a tube of toothpaste from a chemist in the same building as his law firm.

"'I don't know why I did it,' he told me, but that day his child was in hospital undergoing chemotherapy. These are intelligent people who virtually never understand why they did what they did."

And, he says, there is usually a symbolic meaningfulness to the item being stolen. He describes one lady who stole items that she subsequently donated to a charity shop.

One of those items was a wrench. He says the woman didn't understand why she took the wrench but when quizzed about what was going on in her life at the time, she said that her husband, a mechanic, had cancer.

Recent research carried out by Cupchik in North America indicates that more doctors, nurses and police officers have been involved in shoplifting than any other profession.

We can excuse alcoholics but a shoplifter may have the same issues - it is very complicated Barbara Staib, National Association For Shoplifting Prevention

"These are professions that deal with loss - such as loss of life - on a daily basis. They don't process how to handle the experience of loss."

Like many "non-professional" shoplifters, Worrall Thompson has expressed shame over his actions, describing the day he got caught as "the least proud day of my life".

"People can be very ashamed," says Staib. "One woman told us that she wished she was an alcoholic instead of a shoplifter."

The woman explained that if she had told friends that she was an alcoholic and seeking treatment they would commend her for dealing with her problem. But if she told friends that she was a shoplifter and dealing with it, it would be a very different response.

"She said they would be afraid of her," says Staib. "People see shoplifting as more of a black-and-white issue - thou shalt not steal. In the US, someone who shoplifts is a "dirtbag" or a "loser". We can excuse alcoholics but a shoplifter may have the same issues - it is very complicated. It is an addiction and they need treatment.

However, she stresses that none of this makes their behaviour acceptable. "There are some very poor, distraught people who don't shoplift," she says.

The British TV chef has said that while there have been many things going on in his life, including stress and the funerals of a couple of friends, he was not trying to make excuses for his actions.