SCOTLAND YARD detectives investigating the unsolved murder of Georgi Markov, the dissident from Bulgaria killed with a poison-tipped umbrella in London 30 years ago, are preparing to examine secret files showing how the Bulgarian spy service spent £50,000 setting up the attack.

In an attempt to resolve one of the cold war’s most enduring mysteries, a team from the Yard’s counterterrorist command travelled to Sofia earlier this year to request the files from the archives of the Bulgarian secret service.

Yard sources have indicated that police are now hoping to press charges against the key suspect in the case, a Danish petty crook codenamed Agent Piccadilly. The Bulgarian records present compelling circumstantial evidence against the man. He was identified three years ago as Francesco Gullino, a Dane of Italian origin who used to travel around Europe in a caravan pretending to be an antiques salesman.

In fact, the files show, Gullino was recruited by Bulgaria’s spy service after being arrested for smuggling drugs in 1971. He appears to have been briefed in 1977 that he would take part in an attempt to “liquidate” Markov in Britain.

Markov, an opposition activist and BBC broadcaster who had been living in Britain, was poisoned in 1978 when a tiny pellet of ricin was injected into his skin. He had been jabbed by the tip of an umbrella as he waited for a bus on Waterloo bridge.

Before he died, Markov told his wife Annabel that a heavily built man in the queue dropped his umbrella, mumbled “sorry” and hurriedly crossed the road to take a taxi.

He said he initially felt a stinging pain but thought little of the incident. The poison slowly worked its way into his bloodstream and he died three days later.

During their recent trip, the Yard’s officers interviewed about 40 former Bulgarian spies, including General Vladimir Todorov, former head of the communist-era secret service.

The Yard inquiry has been galvanised this month by the publication of a book by Hristo Hristov, a Bulgarian investigative journalist. His analysis of 97 volumes of documents, obtained after a six-year legal struggle, shows that the spy service spent £50,000, of which less than half went to Gullino.

Gullino was last seen in Denmark in 1993.

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