Poisoned former Russian double agent Sergei Skripal wrote to Vladimir Putin asking to be pardoned and to be able to visit his home country, a friend has said.
The former Russian intelligence officer, who came to Britain in 2010 as part of a spy swap, regretted being a double agent and wanted to visit his family, Vladimir Timoshkov told the BBC.
Mr Skripal and his daughter, Yulia, remain in a critical condition after they were poisoned with the highly lethal nerve agent Novichok in Salisbury on March 4.
The attempted assassination sparked a diplomatic crisis between Russia and Britain, which has been supported by its allies in apportioning blame to the Kremlin.
On Friday, EU leaders promised an "unprecedented" diplomatic response to the attack after backing Theresa May's assertion that Moscow was responsible.
Meanwhile, the EU is recalling its ambassador to Russia for "consultations" on the Salisbury attack.
Russia has vehemently denied any responsibility for the incident, while on Sunday Vladimir Chizhov, Russia's EU ambassador, said that "from the legal point of view the Russian state had nothing against him (Mr Skirpal)".
The 66-year-old was accused of working for MI6 over several years, in particular disclosing the names of several dozen Russian agents working in Europe.
He was sentenced to 13 years in a high-security prison in August 2006, before being freed in the 2010 deal which saw 10 Russian sleeper agents expelled from the United States.
According to Mr Timoshkov, his friend, who he had known since school, did not see himself as a traitor as he had sworn an oath to the Soviet Union.
"Many people shunned him. His classmates felt he had betrayed the Motherland," he said.
Russia's ambassador to the UK sent his well wishes to Mrs Skripal and his daughter on Friday, saying he hoped for their recovery.
Alexander Yakovenko wrote to Wiltshire Police detective sergeant Nick Bailey, who was left seriously ill after he was exposed to the poison as he went to the Skripal's aid.
Mr Bailey said his experience had been "completely surreal" after he was discharged from hospital.