Tesla billionaire Elon Musk believes it to be so crucial to free expression and democracy that he decided to spend $44bn to own it.

But Twitter is also rife with hateful abuse, much of it directed at Kent politicians who use the platform as a way to connect with their voters, as Rhys Griffiths reports...

Few of us would accept coming to work every day only to have the most vile and hateful profanities thrown at us by strangers.

People constantly questioning your ability, expressing violent threats towards you, or in the most extreme cases threatening rape and even death.

For our elected representatives, and particularly for female MPs such as Canterbury's Rosie Duffield and Dover's Natalie Elphicke, this is the everyday reality of life online.

Even a cursory glance at tweets aimed at politicians from across the spectrum reveals the darker side of social media.

"Get a f***ing life you stupid b****," one user writes to Ms Duffield. "You f***ing horrible c***," another tells Ms Elphicke.

Twitter - snapped up for a staggering $44bn by the world's richest man Elon Musk - may be the virtual 'public square' of our age - but it is increasingly a distressing place for those whose position puts them squarely in the firing line.

A new study has found Ms Elphicke is on the receiving end of some of the most toxic Twitter engagement directed at any MP of any party.

Research by the BBC Shared Data Unit, which used powerful software to analyse tweets sent to MPs over a six-week period earlier this year, found the Conservative MP for Dover and Deal ranked in the top 10 nationally for the proportion of both 'toxic' and 'severely toxic' tweets directed towards them.

Almost one in every 10 tweets mentioning her twitter handle were identified as 'toxic' - defined in the study as a "rude, disrespectful or unreasonable comment that is likely to make someone leave a conversation".

In processing millions of individual tweets and identifying trends, researchers found the words "stupid" and "idiot" were more likely to score highly in relation topics mentioning female MPs, along with sexual swear words.

Female MPs were also more likely to be called "thick" and "ignorant", while their male counterparts were more likely to be called "liars".

Ellen Judson, who is involved in social media research at the think tank Demos, says accusations of stupidity and ignorance are common insults thrown at women in the public realm.

"Women are often targeted in terms of their intelligence and with sexualised language," she said.

"The effects are really serious - the status quo of online discourse is just untenable.

"We've seen stories of MPs feeling they have to step down because the abuse is just too much, MPs being afraid for their families, and we've seen people say they don't want to go into politics for this reason.

"They have seen the abuse others have received and they think it's just not worth it.

"The psychological toll on individuals is very serious - but there is a serious political toll as well."

Canterbury's Labour MP, Ms Duffield, has found herself subject to abuse on social media because of her stance on trans rights and the debate about gender recognition.

She now sets her own tweets so they can only be replied to by other users who she follows herself or were mentioned in the original tweet - a way of reducing interaction with potentially-abusive strangers on the site.

We attempted to speak to Ms Duffield about her online experience for this story, but she did not respond.

Her fellow Labour MP Jess Phillips, who is a shadow minister for domestic violence and safeguarding, has herself regularly been on the receiving end of abusive vitriol on social media.

She says the content analysed by the recent BBC study - which was publicly accessible online - does not necessarily reveal the very worst abuse politicians are being subjected to.

"Most members of parliament will have blocked a huge amount of it so the public will be able to see things I can't," the member for Birmingham Yardley said.

"In reality the vast majority of the most pernicious abuse comes through private messaging on various different sites and that's often quite hyper-sexualised abuse, cyber flashing and that sort of thing.

"Your email is widely available and so is your constituency address."

'When it becomes not about a subject but about the way you look and about your children and family that's when it crosses the line...'

But should MPs not expect a certain level of robust criticism - even some abuse - given the position they hold?

"The line is crossed certainly when it becomes sexist, racist, over-sexualised," Ms Phillips said.

"Sadly, women politicians suffer huge amounts of thinly-velied or completely direct rape and sexual violence threats.

"When it becomes not about a subject but about the way you look and about your children and family that's when it crosses the line - that's when it's playing the man and not the ball."

In addition to Ms Duffield, we also approached Ms Elphicke and her fellow Conservative MP Tom Tugendhat, who ranked third in Kent's 'toxicity' table. Neither responded to our questions.