Dozens of American-candy shops on Oxford Street are being probed over claims they failed to pay £7.9m in business rates.
Westminster City Council said on Monday that it had seized counterfeit and illegal goods amounting to a £474,000 sum over the past six months.
The council told the BBC that the 30 shops under investigation were “far from regular and legitimate businesses”.
Only a small number of the shops were “serving sufficient customers to be commercially viable,” the council’s spokesperson added.
Instead, officials believe the properties are being used to avoid business rate bills and to “possibly commit other offences.”
The council’s trading standards agency had received complaints over out of date confectionery and counterfeit products.
Last month, trading standards officers seized £58k worth of vapes and unsafe toys from two Oxford Street retailers.
Westminster City Council officers seized more than 4,000 items that were thought to be counterfeit or possibly dangerous to the public.
Items seized in the 26 April raid included vaping devices containing excessive levels of nicotine and which had not been authorised by UK regulators. Some 2023 vapes were found, in addition to 123 counterfeit vapes and 336 snus packets with no safety information.
The council has written to 28 freeholders urging them to consider the impact of such shops in the West End.