YEVGENY is looking forward to adding to his collection of rocks.

That is not his real name, he says with a smile, as he guides me around the second floor of 12, Bolshaya Lubyanka Street. But then these are not real rocks either.

This nondescript building behind the Russian security service headquarters houses the KGB museum — a collection of trophies from the silent war between East and West.

“Yevgeny” is a member of the FSB, the KGB’s successor, assigned to show select visitors the hoard of Western spy toys, ranging from pen guns to false moustaches. And the prize he is waiting for now is the British “spy rock” exposed last month in the biggest such scandal in a decade. “Where else could it go?” he asks. “We’ll call you when it’s here.”

In Britain, the “spy rock” may have been ridiculed as a fantasy out of a John le Carré novel. But the KGB museum, which opened its doors to The Times after a month-long application process, shows that such devices have been used in the spy game for decades.

The museum has four similar “rocks” on display among dozens of “dead drops” seized by the KGB or the FSB in counter-espionage operations. “We have so many, they are hard to count,” says Yevgeny. “Not much surprises us.”

The earliest “rock” on show was used by Martha Peterson, a Vice Consul at the US Embassy in Moscow, who was exposed contacting an agent in 1977. Beside it lie its contents: money, poison, radio equipment, a pistol, a mini-camera hidden in a pen, and film cartridges disguised as a battery.

There is also a note in case anyone found it by accident. “Comrade! You have by chance stumbled upon a stranger’s secret by picking up a packet meant for someone else,” it reads. “Keep the money and gold, but don’t touch the other items so you don’t learn too much and expose yourself to danger.”

No details are provided for the other rocks, but two are displayed with a radio transmitter disguised as a Sony Discman. It belonged to Platon Obukhov, a Russian Foreign Ministry official whose exposure as a British spy in 1996 sparked the last big round of tit-for-tat diplomatic expulsions.

He used the Discman to send data to his British handlers — much as four British diplomats are alleged to have used the spy rock. “This has always been the hardest part of the job, making contact between the agent and the source,” says Yevgeny. “They used to put documents in containers like rocks or shoes. Now it depends on the creative potential of the people designing them.”

One of the more creative trophies is a plastic log used to conceal a melon-sized metal orb that looks suspiciously like a prop from Dr Who. This was planted by the Americans near a Soviet rocket-testing site in Mozhaisk in the early 1970s. It intercepted data and beamed it to US satellites.

Another is a fake branch that the Americans used to disguise a receiver and transmitter attached to a tree near a Soviet airbase in the 1970s.

Most of the exhibits are American. Among the highlights are a pen gun and a poison pin confiscated from Gary Powers, the US spyplane pilot shot down in 1960.

But there is a smattering of British trophies dating back to the 1940s, when a radio, a pen gun and a fake Soviet passport were found on an agent parachuted into the Baltics.

Yevgeny recounts with glee how many early British spies were caught because their documents had stainless steel staples, which unlike the Soviet ones, did not rust.

Another cabinet contains a pipe belonging to Kim Philby, alongside a signed copy of his book, My Silent War. “To my KGB colleagues for good memory, from the author,” it says. Next to it lies a signed copy of an autobiography by George Blake, a British spy who defected and still lives in Moscow.

Yevgeny is diplomatic when asked about his British counterparts. “History has shown that British agents’ level of training is quite high, although there are always some weak points.”

Britain, he concedes, has its own collection of Russian gadgets. “Maybe one day we can set up a joint museum,” he says.

Opened in 1984, the museum is mostly used to educate young FSB recruits and to entertain foreign intelligence officers. Few tourists are allowed in.

But Yevgeny insists that it is designed to show how open the FSB is, not how strong it has become under President Putin, a former KGB officer and onetime FSB chief. “You see now there is nothing scary about the FSB,” he says as we part.

These days, the building even houses a nightclub for FSB recruits, called Lubyanka 12, he adds. But he stops short of inviting me down for a beer.