The staff are employed in Macedonia by playboy Jordan Kamcev, 46, who was once a fugitive in a multi-million pound tax probe.
The former PM wife’s Cefinn garments sell for up to £290 in the store in London’s Oxford Street.
Kamcev is worth around £200million and is being probed by a prosecutor over business dealings in his Balkans homeland.
The textile magnate is under the microscope over land he sold to ex-Prime Minister Nikolai Gruevski which was later re-zoned to allow lucrative construction.
His former empire Media Print Macedonia was raided yesterday and accounts examined from his period of ownership.
In 2004, a swoop by government inspectors reportedly found illegal workers living in cardboard boxes at one of his plants.
Kamcev turned fugitive the following year amid claims he evaded millions in VAT and illegally imported goods.
After a judge issued an arrest warrant, he spent eight months on the run before finally handing himself in. He was later cleared.
It is believed the Camerons’ connection to Kamcev came via former Tory Party treasurer Lord Feldman, who urged David Cameron to run as leader in 2005.
Kamcev has survived two bombing assassination attempts.
One of his main factories, where Sam Cam’s line is believed to be made, sits 15 miles outside the Macedonian capital Skopje.
When our reporter showed up, security pulled shutters closed and chained the gates.
As well as the Macedonian factory, Sam Cam, 45, also uses a manufacturer in Lithuania.
She yesterday insisted Kamcev’s factories had been given the thumbs-up in an ethical audit, also known as SMETA.
Her spokesperson said: “It is of fundamental importance to Samantha Cameron personally that the factories used in the production of Cefinn garments have met ethical audit standards.”
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