It is unclear whether Putin will attend the London Games. He makes little secret of his contempt for Britain, which harbours several prominent Russian political exiles including the oligarch Boris Berezovsky. The UK's judicial refusal to extradite Berezovsky remains a source of Anglo-Russian discord.
MacShane said his move was solely directed at Putin and not at Russia's Olympic sportsmen and women, who would be warmly welcomed.
"There is no anti-Russian feeling in London," he insisted. Instead, he said his target was Russian bureaucrats who enjoyed visiting the UK but denied Russian citizens basic rights at home.
The Home Office has refused to say whether a visa ban for those on the "Magnitsky list" is in place, despite questions from the former Europe minister Chris Bryant, who also supports the move against Putin.
David Cameron and William Hague were willing to "loudly criticise Gaddafi or Bashar al-Assad" but were "mute" when it came to Russia or China, MacShane said, adding: "The time has come to stand up for British values rather than to perch on our knees to Mr Putin in the hope that Russia will co-operate on Syria or Iran.
"There is a dreadful double standard here. Some human rights violations are more equal than others. When Cameron and Hague went to Russia last year, they didn't publicly raise the Magnitsky case. It was shameful."