Jodie Comer was left terrified after an alleged stalker threatened to kill her

The authorities tracked the messages to an unnamed man, 44, in the French city of Roubaix and he was arrested at his home in an armed dawn raid, last month.

A spokesman for Lille prosecutors said: "Following an official approach by the British authorities, a man was taken into custody for acts of harassment against an English actress."

A police source told The Sun newspaper: "We were contacted by British police on June 30 and asked to make inquiries. A local man aged 44 was arrested as a result.

"The investigation is still ongoing but involves threats and harassment made via social media to the British actress Jodie Comer."

It is believed that Jodie was first contacted in June via her Instagram account.

The man is also believed to have tracked down members of her extended family and sent threats to them via Instagram and their personal emails.

During the investigation, Jodie was noticeably absent from Instagram but recently returned to the social media site.

However, she has limited comments on her latest posts.

A spokesperson for Facebook, which owns Instagram, said: “We take threats of violence on our apps incredibly seriously.

"We have clear policies against this and recently announced we’ll take tougher action against people breaking our rules in DMs.”