Police arrested a man in Islington, north London, on Wednesday morning as part of an investigation into unsolicited “honey trap” messages targeting politicians, officials and journalists working in Westminster.

The man, who has not yet been identified or charged, remains in custody. He was arrested on “suspicion of harassment and committing offences under the Online Safety Act,” according to the Metropolitan Police, which has been investigating the messages since April.

The investigation followed a Politico report uncovering how WhatsApp accounts were contacting targets with suggestive and tailored messages that developed into sexually explicit conversations for the apparent sake of acquiring compromising photographs.

There is no evidence to suggest who is behind the activity, although concerns about state espionage were high in Britain in the wake of a government warning about China’s “malicious cyber targeting” of democratic institutions. There is no suggestion the WhatsApp activity is tied to the alleged Chinese targeting.

Detectives said they had taken statements from all of those believed to have been targeted by the messages, including MPs from both the Conservative and Labour parties.

According to Politico, the messages sent to different targets share clear similarities, including an initial claim to have met the recipient at a political venue, displaying “extensive knowledge of their target and their movements within the narrow world of Westminster politics,” before expressing “faux-embarrassment at not being remembered by their target.”

After claiming that they and the target “had a little flirt,” the sender often turned the conversation sexual and shared explicit images purporting to be of themselves.

William Wragg, a senior Conservative MP, confessed to The Times newspaper that he shared the personal phone numbers of several colleagues to a man he met on the gay dating app Grindr.

Wragg told the newspaper: “They had compromising things on me. They wouldn’t leave me alone. They would ask for people. I gave them some numbers, not all of them. I told him to stop. He’s manipulated me and now I’ve hurt other people.”