Romy Andrianarisoa, 47, was accused of seeking substantial payments from Gemfields between 2021 and 2023.

She came into contact with Gemfields' CEO Sean Gilbertson in 2021 and offered to help the company expand its business into Madagascar.

Gemfields, which owns the Faberge jewellery brand, became suspicious and approached Britain's National Crime Agency (NCA), which deployed an undercover officer posing as a consultant negotiating on Gemfields' behalf.

During conversations with the purported consultant, known as "Charles" to protect his identity, Andrianarisoa and her associate Philippe Tabuteau sought around 270,000 Swiss francs ($310,000) between them.

The pair also wanted a 5% stake in a Gemfields company mining in Madagascar which, based on valuations of similar operations in Mozambique and Zambia, would be worth around $4 million.

They were arrested in a London hotel last year and each charged with one count of bribery, after which Rajoelina sacked Andrianarisoa with immediate effect.

Tabuteau admitted the offence last year, but Andrianarisoa pleaded not guilty and stood trial this month at Southwark Crown Court, where she was convicted on Tuesday.

(Reporting by Sam Tobin; editing by William James)

By Sam Tobin