Dozens of shops in London's famous Oxford Street are being investigated for allegedly dodging £7.9million of business tax.
Thirty shops selling American sweets are in the spotlight of Westminster Council, which says it has seized £474,000 of illegal and knock-off items from the stores in just six months.
American candy stores have sprung up along Oxford Street in recent years.
But many of the stores are "far from regular and legitimate businesses", a council spokesperson said.
The council spokesperson said most of the shops did not have enough customers to be "commercially viable".
They added: "Instead, we believe that these properties are used to avoid business rate bills and possibly commit other offences."
Westminster Council has also had complaints about the stores selling out-of-date food, not having price tags on items and selling novelty sex sweets and cannabis confectionery.
Some of the candy shops also sell vapes that contain nicotine levels higher than allowed in the UK, as well as tobacco products with no warning labels.
The stores have also been caught selling dodgy items including fake toys, clothes, jewellery and electrical items.
The shops have also been caught selling fake chocolate - such as imitation 'Wonka Bar' chocolates.
The Mirror understands some of the counterfeit 'Wonka Bars' are being made by people re-wrapping other chocolate in new packaging, then selling it as a legit Wonka Bar.
Other dodgy 'Wonka Bars' may be being made from scratch then sold as the real deal.
Worryingly, some of the candy shops have been selling knock-off sunglasses that did not block damaging light levels.
Council leader Adam Hug said the shops were "a threat to the status" of Oxford Street as London's main shopping district.
He added: "They are not only an eyesore; they are a threat to the status and value of what is supposed to be the nation's premier shopping street," he said.
"The problem is that owners of buildings are turning a blind eye to those who sublet them as it means they are not liable for business rates.
"This needs to stop and we will be stepping up pressure on landlords to make it clear they are responsible for Oxford Street being overrun with these kinds of stores.
"The people selling overpriced and often out-of-date sweets are cheating the UK taxpayer and very often swindling their customers into the bargain."
The council has written to 28 owners of the American sweetshops about the issue, and is also planning legal action against several of the shops.
Westminster Council thinks the shops are dodging business rates, which are normally paid by firms to their local council.
They do this by renting shop space from intermediaries, who in turn rent the store from the ultimate owner.
This murky ownership structure makes it hard for the council to chase anyone for payment.
The council added that people working in the candy shops are "trained not to provide any information to council officers when we visit the premises".
