Critics say Valeriya and Iosif Kobzon, who are to perform at the Albert Hall on 21 October, are propaganda tools for ‘treaty-breaking’ Russia

Protesters are calling on Downing Street to bar two high-profile Russian pop stars who are vocal supporters of Vladimir Putin from entering Britain for a gala performance next week at the Royal Albert Hall.

Crooner Iosif (Joseph) Kobzon and Alla Perfilova – known by her stage name, Valeriya – are due to perform on 21 October at a heavily advertised one-off concert in London.

Critics, who have launched an online petition, accuse the singers of being Kremlin cheerleaders and say the visit, if it goes ahead, will show western sanctions against Moscow over its invasion of Ukraine are ineffective.

In March, Kobzon and Perfilova signed an open letter supporting Putin’s policies in Ukraine and hisRussia’s annexation of Crimea. Perfilova has been a stalwart defender of the Russian government, praising its anti-gay legislation on TV chatshows and backing the decision to jail the punk band Pussy Riot.

Facebook Twitter Pinterest Russia’s president, Vladimir Putin, confers an award on Iosif Kobzon at the Kremlin. Photograph: MISHA JAPARIDZE/AFP/Getty Images

On Sunday, she and her husband-manager, Iosif Prigozhin, sat with Putin in a VIP box at the inaugural Russian Grand Prix. The pair took a series of grinning selfies with Putin, prime minister Dmitry Medvedev and other celebrities, which Prigozhin posted on Twitter. (Also in the box were the Hollywood action star Steven Seagal and the Formula One boss, Bernie Ecclestone.) Last week, Prigozhin sent Russia’s president birthday congratulations. “We trust and hope people will value your contribution to history,” he wrote.

As well as being a Soviet-era crooner, Kobzon is a deputy in the ruling pro-Kremlin United Russia party and a former chair of the Duma’s culture committee. In 1994, the US banned him from entering the country because of his alleged links with organised crime. Despite his denials, Kobzon has been unable to get the US ban lifted. In July, Latvia barred both singers. Its foreign ministry in Riga said: “These individuals, through their own words and actions, have contributed to the undermining of Ukraine’s sovereignty and territorial integrity.”

Valeriya with Putin and Medvedev

Last week, Andrei Sidelnikov, a London-based anti-Putin campaigner, handed a petition into Downing Street calling on Britain to follow Latvia’s example. Sidelnikov said he had nothing against the singers personally, but he argued that their presence in Britain legitimised Russia’s actions in Ukraine and would amount to a PR coup for the Kremlin.

“Using their popularity and public status both Valeriya and Kobzon have become propaganda tools for the international treaty-breaking Russian government,” the petition read. “We petition the UK to follow Latvia and the United States and to deny them entry to the UK.”

Sidelnikov said other members of the Russian elite were watching nervously to see whether the singers would be allowed through UK immigration next week.

Since the crisis in Ukraine started, anti-western and anti-American rhetoric on Russian state television has reached record levels. But Sidelnikov said many of those in government owned lavish properties in London, educated their children at UK private schools, and made frequent trips to Britain. Kobzon’s daughter, son-in-law and grandchildren all lived comfortably in London, he added.

Sidelnikov’s campaign group, Speak Up!, plans to demonstrate outside the Royal Albert Hall on the evening of the concert. The event enjoys official Moscow backing and features on the website of Rossotrudnichestvo, Russia’s federal cultural agency, which is based in Kensington. Its promoters have taken out a series of expensive advertisements for the gig, on tube trains and taxis.

The concert, called Valeriya and friends, features the Royal Philharmonic Concert Orchestra, conducted by Paul Bateman. Perfilova’s son, Arseniy Shulgin, is playing the piano.

Sidelnikov said: “We would be very sad it they are allowed in. We understand it’s up to the British government to act. Free speech is important. But these singers are supporting war in Ukraine and the annexation of Crimea. You can’t separate their politics from showbusiness.”

According to Prigozhin, Kobzon and Valeriya have already received British visas and are looking forward to their trip. The Home Office said: “We do not routinely comment on individual cases.”

Valeriya with husband Iosif Prigozhin and Vladimir Putin

Prigozhin was scathing of Sidelnikov’s action against the concert, tweeting an article that described the anti-Putin activist as a provocateur who was simply seeking to gain British asylum. Sidelnikov dismissed this as rubbish. “I got political asylum six years ago,” he said.

So far, 3,600 people have signed the Change.org petition. It accuses Kobzon of being “always deeply politically and ideologically engaged with the ruling regime” and urges the UK government to “stop Iosif Kobzon and other members of the Kremlin’s cheerleading team from entering the UK or any other democratic country”.

Of the two singers, Kobzon is the more famous. During communist times he was the Soviet Union’s equivalent of Frank Sinatra, known both for his party youth anthems and sugary romantic ballads.

Supporters acknowledge that he is close to power but point out that he has been a loyal friend to those who have fallen from it, including Moscow’s former mayor Yuri Luzhkov, who was sacked in 2010. In 1980, Kobzon helped arrange the funeral of the singer-songwriter Vladimir Vysotsky. The Soviet authorities never approved of Vysotsky’s work.