Russian president Vladimir Putin has described Sergei Skripal, the former spy poisoned with novichok, as “a traitor” and “scum”.

In an extraordinary address at the Russian Energy Week in Moscow, the president rejected British allegations of Russian involvement in the affair with a mix of scorn and sarcasm.

“You’re saying some guys arrived in Britain to poison some tramps?" Mr Putin said, referring to the accidental secondary poisoning of Dawn Sturgess and Charlie Rowley in Amesbury. "What is this nonsense about?"

Mr Putin said coverage of the Salisbury poisoning had distorted who Mr Skripal really was.

“I see that there is this theory that Skripal was almost some kind of human rights activist,” he said. “He’s just a spy who betrayed his people. A national traitor, that’s who he is. He’s just scum.”

Using the derogatory term “shpion” (spy) rather than “razvedchik” used for Russian agents serving the motherland, the president went on to compare Mr Skripal’s actions with prostitution.

“Jiggery-pokery between special services hasn’t just appeared just now. Spying, like prostitution, is one of the most important professions in the world.”

“He’s just a spy who betrayed his people. A national traitor, that’s who he is. He’s just scum.” Vladimir Putin on Sergei Skripal

Britain has accused Russia's military intelligence services GRU of ordering the attempted assassination of Sergei Skripal in Salisbury in March.

In September, British detectives named two suspects “Ruslan Boshirov” and “Alexander Petrov”, who they claimed were Russian nationals and GRU officers.“ Independent investigations have since persuasively shown that “Ruslan Boshirov” is in fact a decorated GRU colonel called Anatoly Chepiga. Intelligence blunders revealed in the course of those investigations may also have inadvertently outed dozens of Russian agents.

In his 18 years as leader, Mr Putin has cultivated a hard-line rhetoric, and frequently employs informal, direct and coarse language. He has talked about “drowning terrorists in the toilet”, compared protest ribbons to condoms, and has offered circumcisions to journalists who asked about human rights in Chechnya.

Today’s statement was in that tradition – but it also went against the grain of recent attempts by the Kremlin to take an embarrassing story off the front pages.