Katrin Ivanova, 33, Vanya Gaberova, 30, and Tihomir Ivanchev, 39, all from London, deny a charge of conspiracy to spy.

Ms Ivanova also denies possessing multiple false identify documents.

Prosecutor Alison Morgan KC told the court Roussev and Dzambazov had already admitted being part of the same espionage activity.

Three defendants, along with others, “spied for the benefit of Russia” between 2020 and 2023, Ms Morgan said.

She added that they “sought to gather information for the benefit of Russia, an enemy of the UK”, including information about various targets, both people and locations, of particular interest to the Russian state.

Ms Morgan said the defendants were “sophisticated in their methodology; carrying out surveillance activity of individuals and places; manufacturing and using false identities and deploying advanced technology to acquire information”.

She said the defendants had “obtained imagery” and “compiled detailed reports on their targets”.

“They were paid significant sums of money for their actions. And they all knew why they were being tasked to conduct their operations. Their activity was being undertaken for the direct or indirect benefit of Russia,” she said.