MOSCOW, May 20 (RAPSI) - An individual referred to as a “US-based former Russian spy” and a key witness in the investigation of the 2006 death by polonium-210 poisoning of former Russian intelligence officer Alexander Litvinenko has expressed willingness to provide evidence during a public inquiry, according to The Independent.

The Independent reports that the witness’ cooperation is expected to increase pressure on the UK government to drop the formal inquest presently underway.

The inquiry hit a stumbling block last week when British Coroner Sir Robert Owen upheld an application to keep certain key evidence secret based on public policy concerns.

According to RIA Novosti, UK Foreign Secretary William Hague had earlier applied to exclude material from the inquest that related to the involvement of Russian state agencies, as well as evidence pertaining to the question of whether the UK’s security and intelligence agencies could have prevented Litvinenko’s death.

In a judgment published Friday, Owen wrote "My provisional view is that to entertain these issues on the basis of the available open evidence, but to disregard the [national security] evidence... would be to fail to discharge my duty to undertake a full, fair and fearless inquiry into the circumstances of Mr Litvinenko's death.”

He continued, "The same could be said of a decision to remove the issues from scope. But the better course is arguably not to address the issues at all rather than to do so an incomplete, inadequate and potentially misleading basis.”

According to The Independent, Litvinenko’s widow has urged the replacement of the present inquest with a public inquiry, categorizing Owen’s decision as a “decision to abandon his search for the truth about Russian state responsibility.“

Litvinenko, 43, died on Nov. 23, 2006 shortly after obtaining British citizenship. Doctors announced that they found high levels of polonium-210 in his body.

The British authorities have accused former security agent Andrei Lugovoi, who is now a businessman and a lawmaker, of involvement in the murder. Lugovoi has dismissed the accusations as politically motivated.