A HASLEMERE teenager has been arrested by the Metropolitan Police cyber crime unit in its investigation into a series of cyber attacks on high-profile parenting site Mumsnet, one of which involved armed police being called out to the home of the co-founder Justine Roberts.

The 17 year old was arrested in Haslemere, on October 22, on suspicion of conspiracy to commit crimes under the Computer Misuse Act and has been bailed to a date in January.

Another 17-year-old youth from Knutsford, Cheshire, was interviewed under caution on the same day, but he was not arrested.

Ms Roberts – who is married to BBC Newsnight editor Ian Katz – suffered a “swatting attack” in August, a type of harassment in which a perpetrator calls the emergency services out to their victim on a false pretence.

The Met received an anonymous phone call from someone reporting she had been murdered and her four children taken hostage by a gunman. Eight police officers were dispatched to her London home in the middle of the night, five armed with machine guns, accompanied by police dogs.

The family was away on holiday and only their 21-year-old Spanish au pair was at home to face the commotion.

Around the same time, threatening messages, including “RIP Mumsnet”, were tweeted and appeared online and a group calling itself @DadSecurity temporarily brought down the site, which has 7.7 million members, by flooding it with data.

The site’s administrative functions were hacked into and the passwords of 3,000 users were posted online.

Ms Roberts said: “The hackers were discussing what they were doing on a public forum and we were reading their discussions.

“They were pretty vile – racist, sexist, misogynistic.

“It was not a nice place to be, to be reading day to day these horrific conversations full of hate and bile.

“They published where I lived, the names of my children online, and where they thought they went to school.

“In the US, they view it as civil terrorism but as far as I know, mine was the first instance in this country of swatting, so the police were much less worried about it.

“Once it had gone a bit public, the cyber terrorism unit got involved and since then they have taken in seriously.”

The pressure group Fathers4Justice, which has campaigned against the forum, condemned the cyber attack and said it had no connection to the swatting attack, perpetrated by a hacking group using the Twitter name @DadSecurity.

In a statement, a Met spokesman said: “Police were called at approximately 00:15hrs on August 11 to a residential address in Islington, following a report that a man had murdered a woman at the address.

“This was followed by a second call during which the caller stated he had members of his family held in a room. This call was assessed as requiring a firearms response.

“Local officers and firearms officers attended and carried out an assessment. The incident was treated as a hoax and the police response explained to those at the address.”