Alexander Litvinenko inquiry opens
Alexander Litvinenko was poisoned by radioactive polonium in 2006

A key suspect in the assassination of ex-KGB spy Alexander Litvinenko will give evidence at the inquiry into his death, it was announced on Monday (15 June).

Former Soviet army officer Dmitry Kovtun will provide testimony via video-link after the inquiry chairman, Sir Robert Owen, granted him "core participant status."

"Sir Robert Owen, chairman of the Litvinenko Inquiry, has designated Mr Dmitri Kovtun as a core participant to the Inquiry, pursuant to rules 5(2)(a) and (c) of the Inquiry Rules 2006," a statement issued by the inquiry said on Monday.

"Sir Robert is satisfied that Mr Kovtun has complied in full with his directions dated 2 April 2015."

No date has yet been set for the testimony.

Litvinenko, 43, died on 23 November 2006, three weeks after meeting Kovtun and former Russian spy Andrei Lugovoi in the Pine Bar at the Millennium Hotel in Mayfair.

During the meeting, he drank tea containing a fatal dose of the rare isotope polonium-210.

Both men deny any involvement in Litvinenko's death, with Russia refusing to extradite the pair.

Kovtun and Lugovoi initially refused to take part into the inquiry, which opened in January.

In March, Kovtun changed his mind and decided to give evidence.

He previously said he believes Litvinenko died as a result of "inadvertent suicide" after being exposed to polonium-210.

"My main version is that it was an accident," he told a Moscow news conference in April. "I am more than certain he dealt with polonium without even knowing it. It might have been a leak and polonium was accumulating in his body gradually."

He added: "I don't know whether he had it on him or someone gave it to him. It's entirely possible he carried something with him and polonium gradually accumulated in his organism, and led to his death."

Lugovoi has also maintained his innocence, pointing the finger of blame at British intelligence agency MI6, the late Russian oligarch Boris Berezovsky, and the Russian mafia.

Litvinenko had been an officer with the Federal Security Service - the successor to the KGB - before he fled to the UK and sought political asylum in 2000.

He was an outspoken critic of the Kremlin, accusing Russian president Vladimir Putin of being responsible for ordering his poisoning before his death.