We were alarmed allegations have been made that Jeremy Corbyn, the Leader of the British Labour Party, was a confidant of the State Security of the communist Czechoslovakia. We were prosecuted by State Security because of our work for Charter 77 ourselves. We have learned about their methods from our own experience, and from the experience of our relatives and colleagues.

We thought the times when State Security could influence the lives of people in Czechoslovakia had ended in 1989. We consider it unacceptable that it could still influence the political situation even in other countries.

The claims by a former officer of the Czechoslovak State Security service, who operated in the 1980s in London with a diplomatic cover, underlined the dangers of uncritically accepting information given about its activities.

The credibility of this information was refuted by the director of the Czech Archive Světlana Ptáčníková. It was also exposed as apparently false by a leading Czech expert of that era Radek Schovánek. Their explanations are based on rock-solid evidence that excludes any possibility that the accusations against Jeremy Corbyn could be true.

Slovak courts recently ruled that testimonies of former informers and officers of the State Security of communist Czechoslovakia are a priori unreliable and useless. We strongly condemn the fact that some records, dozens of years old, could still be misused by the discredited ruins of the communist regime.

František Bublan, Petr Kajnar, Eva Kantůrková, Petr Pithart, Petr Pospíchal, Jan Šabata, Petr Uhl

• František Bublan is a member of the Czech Senate. He was the director of the Foreign Intelligence Service.
• Petr Kajnar is a politician. He was a mayor of Ostrava, third largest Czech town.
• Eva Kantůrková is a Czech author. She was a spokesperson for Charter 77.
• Petr Pithart was the first prime minister of the Czech Republic after the Revolution in 1989. For six years he served as the president of the Czech Senate.
• Petr Pospíchal is a journalist and diplomat.
• Jan Šabata is a publisher.
• Petr Uhl is a journalist. He was the director of the Czech Press Agency.