London Mayor Boris Johnson believes it would be wrong to break the capital’s cultural ties with Moscow because of anti-gay legislation passed by the Russian Parliament – although the senior Tory “is deeply concerned” by the situation.

Green Party London Assembly Member Darren Johnson tabled a formal question urging the Mayor “to end London’s symbolic link with the Russian capital unless what is widely perceived to be discrimination and hostility perpetuated by the Russian Government towards gay people there has ceased.”

In response, the Mayor said: “I am proud that London is a fantastically diverse city, with all Londoners, regardless of their age, sexuality, religion, gender or race, able to benefit from the progress London has made over the past few years. We stage events to bring communities together, including Maslenitsa, as well as vibrant and visible Pride celebrations. I also supported the bid to stage the 2018 Gay Games in London.

“I do share your deep concern about the abuse of LGBT people in Moscow and throughout Russia. However, I believe that we can better challenge prejudice through engagement. Isolation will not achieve change.”

Along with London, other UK cities including Glasgow and Manchester have been urged by some LGBT campaigners to end their twinning arrangements with various Russian municipalities – although so far none have followed suit.

A federal bill banning gay “propaganda” was signed into law by Russia’s President Vladimir Putin in June.

It prescribes fines for providing information about homosexuality to people under the age of 18 – ranging from 4,000 roubles (£78) for an individual to 1m roubles (£19,620) for organisations.

Yesterday, Sir Elton John announced he wouldn’t be cancelling a planned Moscow concert in December despite the country’s anti-gay laws. He said: “As a gay man, I can’t leave those people on their own without going over there and supporting them. I don’t know what’s going to happen, but I’ve got to go.”