The Instagram account of former English Defence League (EDL) leader Tommy Robinson was removed “in error”, according to the Facebook-owned social network.
Robinson was released on bail earlier this month after winning an appeal against a contempt of court finding.
On 6 August he reported that his Instagram account had been “deleted”.
Instagram said it was working on improving its process for evaluating content.
“They have now deleted my Instagram account. Facebook will soon close us down,” wrote Robinson on Facebook.
In a statement, Instagram said: “The account @realtommyrobinson was removed in error and has since been reactivated.”
Instagram said that the account had been reported for violating the site’s community guidelines regarding bullying, but the removal was a mistake that occurred when the account was under review.
It comes after a number of US tech firms took steps to remove content from conspiracy theorist Alex Jones in recent days.
Facebook took down Jones’s InfoWars page and he also had his YouTube channel removed.
Hundreds of his podcasts were also deleted from Apple’s iTunes and Podcasts apps.