The Russian agent running a UK-based spy ring joked that he could supply “nukes” if a client could pay, a court has heard.

Jan Marsalek, the fugitive boss of a German tech company, and Orlin Roussev, who was running a spy ring for him from a guest house in Great Yarmouth, were also involved in money laundering and the trade of weapons and blood diamonds around the world, messages have shown.

The details have been revealed as part of the sentencing hearing for Roussev and his team of Bulgarian agents who were arrested in February 2023 after Britain’s biggest spying investigation.

Marsalek, their tasker from Moscow, had boasted that they could supply “even nukes” if the client could pay.