James Goddard, the “yellow vest” activist at the centre of controversy over the harassment of MPs and journalists outside parliament, has reportedly been arrested on suspicion of committing public order offences.

The pro-Brexit activist was arrested outside St James’s Park tube station in central London on Saturday in connection with incidents that happened in Westminster on Monday, the Metropolitan police said.

Scotland Yard began an investigation after Conservative MP Anna Soubry was surrounded by protesters on Monday outside parliament and called a “Nazi”. Police did not confirm whether Goddard’s arrest was related to the incident.

His supporters claimed he was about to hand himself in to Holborn police station, according to the BBC journalist Daniel Sandford.

The police, who would not name Goddard, said: “We can confirm that a man in his 30s was arrested at 11.42hrs on Saturday 12 January outside St James Park tube station on suspicion of a public order offence.”

The man was later released on bail until early February, the force said.

Both pro-Brexit and anti-Brexit supporters held separate protests in central London on Saturday, each wearing yellow vests. The march organised by the People’s Assembly Against Austerity appeared closer to the movement’s original French gilet jaune roots, with the rally in support of improving living standards for the poor. It also included factions from the Socialist party and anti-racist campaigners.

The harassment of Soubry was widely condemned. Commons speaker John Bercow said he was concerned about the targeting of female MPs and journalists.