New documents have confirmed that the operation that led to the 1978 murder of Bulgarian dissident and playwright Georgi Markov, code name "Wanderer", in London was a topic of discussion between the KGB and the Bulgarian intelligence services that Bulgaria's communist ruler Todor Zhivkov controlled. The subject of these discussions was the planning of how to disarm the playwright.

The documents confirm that agent Piccadilly, the only suspect in the Markov's murder investigation, was specially trained in 1978, sent on a mission and subsequently invited to holiday in Bulgaria, where he was presented with medals by the country's then-secret police State Security.

A secret agreement between the KGB and the Bulgarian communist-era intelligence services to provide Bulgaria with access to fast-acting poisons and devices for their delivery has been discovered as well.

"Piccadilly" (Francesco Gulino), an agent of the Bulgarian intelligence services, underwent special training in early 1978. Before this, on the instructions of the Bulgarian communist intelligence, he had been sent on at least four occasions to London using fake passports. Immediately after Markov's murder in September 1978, the same agent was summoned back to Bulgaria, where he took a holiday and was presented with a medal. For the next 12 years, the Bulgarian intelligence services did not give him any serious assignments, and by the time 1990 arrived, when he was "frozen", he had been paid a sum of about $30 000, presented with another medal and sent on three more holidays at the expense of Bulgarian intelligence services.

All this has been revealed in the dossiers of agent Piccadilly, which are currently stored in the archives of Bulgarian's National Intelligence Service (NIS). The most important of these documents will be published in Bulgarian-language Dnevnik daily in a series of articles starting on September 8.

This is possible because of Dnevnik's investigative journalist Hristo Hristov, who was granted access to the dossier of agent Piccadilly and more than 100 other files from the archives of the State Security's First Chief Directorate (which was the international intelligence branch of State Security) after a three-year legal battle.

Hristov had been initially refused access to key archives containing information about the murder of Georgi Markov by the director of NIS, General Kircho Kirov. The court battle ended in the Supreme Administrative Court, which issued an unprecedented ruling in favour of Hristov.

As a result of this ruling, for the first time in Bulgaria's history, documents from the archives of the communist intelligence services will be made public. These documents have remained behind closed doors for the past 18 years and are directly linked to operations carried out by the State Security First Chief Directorate aimed at liquidating Markov.

Documents from the Piccadilly dossier were requested by the British and Danish authorities in 1993 in order to arrest  Gulino, but Bulgaria refused to provide them and the man disappeared from Copenhagen, where he had been based by Bulgaria's intelligence services since 1975.

In May 2008, Scotland Yard  again requested the Piccadilly files as providing the most important evidence in Markov's case; at present, it is not clear whether the Bulgarian authorities have agreed to provide them.

In the previously inaccessible archives, in addition to the Piccadilly dossier, Hristov came across other shocking documents.

One was the secret agreement between the KGB and State Security, based on which the First Chief Directorate was granted access to fast-acting poisons and mechanical devices for their silent delivery. The agreement was signed between the Bulgarian and Soviet intelligence services in 1972 by the their then-directors, Bulgarian Dimitar Kyosev and Russian Fyodor Mortin.

The document required the Soviet intelligence services to provide experience and facilities for the selection and training of agents who would perform the so-called serious operations (sabotage, kidnapping, murder). After the fall of communism, the former director of "K" department of the Soviet intelligence services, General Oleg Kalugin, publicly admitted that Zhivkov had made a request for KGB technical assistance in the liquidation of Markov, but the successors to the KGB in Russia today have denied these allegations.

The archives of the Bulgarian intelligence services also reveal documentary evidence that the operation led by Bulgarian intelligence services against Markov, ie, Wanderer, was a topic of discussion in the KGB. During the investigation, it became clear that the intelligence services had planned a detailed study of the Wanderer situation for the purposes of performing a "serious operation" (SO) and the "disarming of the target". Other documents discovered by Hristov in the Markov investigation used the term "neutralised" as opposed to "disarmed".

In 2005, Hristov published a book, entitled Kill Wanderer, about the murder of Georgi Markov, based on detailed studies of all the archives in Bulgaria, with the exception of the archives of the NIS.

This new investigation is based almost entirely on documents from the archives of the communist intelligence services of Todor Zhivkov and will be published under the title The Double Life of Agent Piccadilly.

The new disclosures comes 30 years after Markov's murder and only days before the Bulgarian investigation into the case will be closed because of the expiry of the 30-year statute of limitations for criminal investigations. In recent years, the investigator into the case, Andrei Tsvetanov, who was appointed in 2001, has been promoting the theory that Markov's death was a result of medical error by the doctors treating Markov in 1978.

At the same time, Tsvetanov ignored all the evidence gathered in the case by the previous investigative team (including the Piccadilly files) that prove that the murder had been prepared and carried out by the First Chief Directorate with KGB assistance.

If Tsvetanov closes the case saying that the death was a result of a medical error, this will cause a scandal at a moment when the Bulgarian judiciary is being criticised by the European Union for its inefficiency. The new disclosures have raised the question of whether the Bulgarian authorities' investigation into the Markov murder has been sufficiently objective and why the new archive evidence has not been included in it.

The Wanderer

Georgi Markov was a well-known novelist and playwright in 1960s Bulgaria. In 1969, Markov went to Italy to visit his brother and decided to not return to Bulgaria after a number of his plays were censored. In 1972, he started working for the Bulgarian desk of the BBC World Service in London. The same year, the communist regime sentenced him to six years and six months in prison for his defection to the West. The Bulgarian communist Secret Services started a file on Markov under the code name "Wanderer" after he started broadcasting highly critical reports against Todor Zhivkov and Bulgaria's communist regime on Radio Free Europe . On September 7 1978, Markov was waiting at a bus stop near Waterloo Bridge in London, when he was "accidentally" bumped into by a man holding an umbrella, which pricked him. Later, he developed a high fever and was admitted to a hospital, where he died on September 11 at the age of 49, with doctors failing to identify the cause. His death became known as the "Bulgarian umbrella murder".