Presidential spokesman Dmitry Peskov has insisted the Kremlin has "nothing to add" to reports linking a serving military intelligence colonel to the Salisbury novichok poisoning of double agent Sergei Skripal and his daughter Yulia.

In an angry exchange with journalists, he said the Kremlin would not discuss the findings of an independent investigation by Bellingcat/Insider. That investigation named 39-year-old Colonel Anatoliy Chepiga for the first time, documented a history of his service, and provided a photographic match with a man UK prosecutors have charged with murder.

But Mr Peskov claimed to be confused.

"In the last few months ... there have been a number articles and investigations about the Skripal affair," he said. "No-one can work out which of them are truthful and which are lies,"

He suggested journalists should address questions to "relevant agencies," and said Moscow would only respond if it was given access to "raw data" by "official sources."

Moscow has regularly complained about not being given access to the British investigation. The British side says that is not going to happen, referring to past experience investigating the death-by-polonium of former FSB agent Alexander Litvinenko. Then, the Kremlin allowed British detectives to interrogate the main suspects. But they limited the number of questions that could be asked, and reportedly handed blank tapes to the investigating officers.

Karen Pierce, UK Ambassador to the UN presented the British position in blunt terms during an extraordinary session of the Security Council in March. Russia asking to be part of the investigation was akin to "an arsonist investigating his own fire," she said.

Earlier in the day, Russian state media carried an interview with Alexander Borzhkov, a man they identified as Colonel Chepiga's former commander. Mr Borzhkov confirmed he trained a "certain" Chepiga at the the Far-Eastern Military Command Academy in the city of Blagoveshchensk, but any attempts linking him to the Salisbury incident had "a whiff of mild schizophrenia."

The interviewer failed to ask the simple question: are Chepiga and the man presented as Ruslan Boshirov the same person?

Mr Peskov also said the Kremlin would not attempt to identify the officer in question — "we don't do searches and identifications."

But he also questioned the photographic evidence presented in the Bellingcat / Insider report.

"There are 10 Stalins and 15 Lenins on Red Square and they all look like the original," he said, referring to the lookalike artists that mingle with tourists in central Moscow.