The correspondence released by the Russian Prosecutor General's Office covers the period now-Prime Minister Theresa May served as home secretary. It is presented in the office's Telegram channel.
"This letter, as well as later addresses by Russia's Office of Prosecutor General to Theresa May, remain unanswered," the office said in a statement.
On April 9, the Prosecutor General's Office held a briefing on the circumstances of the poisoning of former Russian double agent Sergei Skripal and his daughter Yulia. The office pointed out that the Skripal case is going just as the case of Berezovsky as well as that of Alexander Litvinenko went.
It was also reported that "copies of individual documents from relevant criminal cases, including correspondence with the UK Home Office, including directly with Mrs. May during her service as home secretary, will be presented."
Berezovsky, who was involved in numerous criminal cases in various countries, died in his home near London in 2013. His death was determined to be a suicide.
Litvinenko, a former Russian spy, left Russia for the UK in 2000 after several criminal cases were opened against him. He was poisoned in November 2006 with what was determined to be polonium-210. The UK maintains that his death is Russia's doing.