David Smith, 58, who worked as a security guard at the embassy, was due to enter pleas to nine charges under the Official Secrets Act dating back to May 2020.
Wearing a grey T-shirt and tracksuit bottoms, he spoke only to confirm his name.
Alistair Richardson attended for the prosecution but Smith’s barrister was absent, with the defendant’s interests represented by solicitor Russell Nicholson.
Addressing the prosecutor, Mr Justice Wall said: “I know the defendant is not represented by counsel today but Mr Nicholson is here to represent his interests.
“Obviously that will limit the amount we can achieve but I felt it was important to maintain this listing so the case can advance as much as possible, so we can keep the trial date in February.”
The senior judge set a new plea hearing for October 4 when he will deal with any other directions in the case.
He added: “At the moment I understand why defence counsel are not in attendance – there is no guarantee that situation will have changed by that date.”
If there is no change, the senior judge asked that the defence counsel communicate with the court and indicate the likely pleas.
Smith, who was living in Potsdam, was arrested by German police on August 10 last year and extradited to the UK in April.
According to the charges, Smith gathered information from the embassy and passed it to someone he believed was a representative of the Russian state, as well as other alleged offences.
The charges allege Smith communicated by letter with “General Major Sergey Chukhurov, the Russian military attache based out of the Russian Embassy, Berlin”.
The material “contained details about the activities, identities, addresses and telephone numbers of various members of Her Majesty’s Civil Service”.
Smith allegedly committed acts “prejudicial” to the safety and interest of the state by gathering information classified as “secret” about the “activities of Her Majesty’s Government”.
He allegedly “collected material relating to the operation and layout of the British Embassy in Berlin”, with that information thought or intended to be “useful to an enemy, namely the Russian state”.
Smith also allegedly made unauthorised photocopies of documents, video recordings of the embassy’s CCTV system and “kept sim card packaging” he had been asked to dispose of.
The charges claim he gave information about building repairs at the embassy after being approached by someone he “believed to be a member of Russian Military Intelligence (the GRU)”.
Following the brief court hearing, Smith, now of no fixed address, was remanded into custody.
He is due to go on trial at the Old Bailey on February 13 next year.