Piers Corbyn was arrested yesterday after leaflets were handed out which compared vaccines to the Holocaust.
Police had been urged to investigate the leaflets after they were posted through letterboxes in Southwark and Lambeth.
The Met Police confirmed they arrested a 73-year-old man on suspicion of malicious communications and public nuisance yesterday in Southwark in connection with the leaflets.
The force also arrested another man, aged 37, on suspicion of a public order offence in Bow.
Officers refused to confirm the identity of either man.
But Mr Corbyn, the elder brother of former Labour leader, Jeremy, today denied that the leaflets – which mocked up Auschwitz’s gates with the slogan ‘Vaccines are safe path to freedom’ – were antisemitic.
He told the Jewish Chronicle: “The idea we’re antisemitic in any way is completely absurd.
“I was married for 22 years to a Jewess and obviously her mother’s forebears fled the Baltic states just before the war because of Hitler or the Nazis in general.”
He also told the publication that he had volunteered to be questioned by officers.
“Both men were taken to a south London police station,” said a Met spokesperson.
“They have since been bailed to return on a date in early March.”