Five Bulgarian nationals in custody in the UK will face a four-month trial next year on charges that they spied for Russia, a judge ruled on Friday.

Orlin Roussev, Bizer Dzhambazov, Katrin Ivanova, Ivan Stoyanov and Vanya Gaberova are alleged to have been part of a “network” conducting surveillance for Russia “with another person known as Jan Marsalek and others unknown”.

Marsalek is the Austrian former chief operating officer of payments firm Wirecard, who became a wanted man in Germany over fraud allegations.

He has not been charged in the British case.

Roussev, 45, Dzhambazov, 42, Ivanova, 32, Stoyanov, 31, and Gaberova, 29, appeared at the Old Bailey Court in central London via video link.

Judge Jeremy Baker remanded all five in custody until March, and set a trial date for October 28 next year, It is expected to last four months.

The defendants are each charged with “conspiring to collect information intended to be directly or indirectly useful to an enemy for a purpose prejudicial to the safety and interest of the state”.

The court was previously told that the five were arrested by counter-terrorism police in February under the Official Secrets Act.

A large part of the alleged surveillance took place overseas but was coordinated in the UK.

The alleged offences are said to have occurred between August 30, 2020 and February 8 last year.

Roussev, Dzhambazov and Ivanova are also charged with “possession of false identity documents with improper intention”.