At 2.29pm on 29 July 2013, Isabella Sorley, a then-23-year-old advertising graduate from Newcastle, said on Twitter: “Me doing something when tired only leads to one thing, me loosing [sic] my temper, but I’m sure sleep and wine will sort me out later.”

Twelve hours later, between 2.25am and 2.55am, she sent six tweets to two people: feminist writer Caroline Criado-Perez, who was campaigning for a woman to be featured on the £10 note, and Labour MP Stella Creasy, who supported the campaign.

The tweets said: "Fuck off and die…you should have jumped in front of horses, go die; I will find you and you don’t want to know what I will do when I do… kill yourself before I do; rape is the last of your worries; I’ve just got out of prison and would happily do more time to see you berried; seriously go kill yourself! I will get less time for that; rape?! I’d do a lot worse things than rape you."

The press, whose interest in online abuse cases reached a peak in the summer of 2013, invariably describes internet trolls as "vile", but in person, when BuzzFeed News meets her in Newcastle, Sorley, now 24, is confident and polite, and at times witty and self-deprecating. It's hard to imagine her getting a kick out of telling someone to "kill yourself before I do".

So how did she end up sending someone death threats at 2am?

"Alcohol," she says without pausing to think. "I’m a horrid drunk and it's just stuff I say when I'm drunk. I've read police statements of what I've said when I'm drunk and I've heard it read out in court and it's all alcohol. It makes me really mean and nasty.

"It's just something inside me … and I guess Twitter just became an outlet for that."

Three days before Sorley sent the offending tweets, 25-year-old John Nimmo in nearby South Shields sent abusive tweets to the same two women via five pseudonymous accounts. His 20 tweets between 27 July and 29 July included these statements:

"Ya not that gd looking to rape u be fine; I will find you; come to geordieland bitch; just think it could be somebody that knows you personally; the police will do nothing; rape her nice ass; could I help with that lol; the things I cud do to u; dumb blond bitch."

Nimmo and Sorley live just 12 miles apart, but don’t know each other (BuzzFeed News met them separately). They were both sentenced on the same day for the exact same crime.

On 24 January 2014, at Westminster Magistrates’ Court, Sorley was sentenced to 12 weeks in prison and Nimmo to eight for sending malicious messages, under section 127 of the Communications Act 2003.

They served half their sentences in London jails and were each ordered to pay £400 to their victims – although the judge allowed them to take up to three years to do so because of their lack of funds.

In the aftermath of the tweets, both Criado-Perez and Creasy spoke of the lasting effect of abusive messages like these, and Creasy later admitted to having installed a panic button in her home. Criado-Perez said she struggled to eat, sleep, and work at the height of the abuse. She declined to comment for this article; Creasy has not yet responded to our requests.

More and more people are being arrested and convicted for internet trolling. According to figures from Big Brother Watch, 6,329 people across the UK were charged or cautioned for malicious communications-related offences between November 2010 and November 2013.

Of these, at least 4,259 were charged and 2,070 were cautioned, and 355 cases involved social media.

Creasy and Criado-Perez received torrents of abuse from scores of Twitter users over the summer of 2013 from as many as 147 Twitter accounts, so what made Nimmo and Sorley so special? Twelve months on from their release from prison, what do two of the country’s most notorious internet trolls think about the case now? Were they especially wicked compared to all the other Twitter trolls on the bandwagon? And was it right for them to be punished with imprisonment?

What is not in doubt is that Sorley for several years had a serious alcohol problem.