When Wavertree MP Luciana Berger passes the steps at the back of Central Lobby in the Palace of Westminster, she is able to give a nod to her great-uncle Manny – which is a good trick given that he died in 1986. Manny Shinwell, the famous Red Clydesider, is one of few people who was not a prime minister to have a bust in parliament. “It’s amazing to see that and be part of that heritage,” says Berger, who has read all of her great-uncle’s books. He was also, she points out, the last parliamentarian to throw a punch in the chamber. Shinwell, who was of Polish-Jewish extraction, took exception to a Tory MP telling him to “get back to Poland” and lashed out. “And good for him!” says Berger.

Were he alive, Shinwell would be as proud of his great-niece’s defiance as she is of his, given the scale of antisemitic provocation she, too, has had to endure. Three men have been convicted of abuse against her and there’s even been an international social media campaign – #FilthyJewBitch – organised against her. But that is not the only reason that Berger, who resigned as Labour’s shadow minister for mental health following Brexit, has been targeted. An atmosphere of contempt and violent aggression has recently begun to pervade political discourse. The most extreme illustration of it was the murder of politician Jo Cox, but others have had to endure aggressive and misogynistic intimidation. None more so than Luciana Berger. “It’s a combination of being young, female and Jewish,” she explains.

“Look,” says Berger, who was the director of Labour Friends of Israel for three years before becoming an MP, handing over her phone. She shows me a website which contains a vitriolic catalogue of messages, urging people to tell her – and I can’t even repeat what they call her – that Hitler was right – six million times.

The campaign, organised because antisemites were angry at one of their own being jailed for abusing Berger, has been online since 2014. Could Twitter do more to control it? “Of course they could!” Berger says. The effects of receiving these messages go deep. “It’s personal and sometimes very extreme in its nature. Sometimes it’s pornographic, sometimes violent, often very misogynistic. At its peak, there were 2,500 tweets. Some people who were shown just one message couldn’t believe it, so to receive thousands is difficult.”

Garron Helm was jailed in 2014 for sending this antisemitic tweet to Berger.

Difficult, too, for her family. We’re sitting in Berger’s constituency office in Wavertree, Liverpool but, a few weeks before I’d gone to watch her at the mayoral hustings. “Where’s Luciana’s husband?” I asked her adviser, looking round for someone who might approximate to the male equivalent of a politician’s wife. “That’s Alistair,” said the adviser, pointing to a laid-back figure in jeans and T-shirt. They met at a music industry event and he contacted her afterwards, claiming she’d given him the eye. Had she, I asked her. “When I got the message on Facebook, I didn’t even know who he was! I kept refusing to go out with him but he wouldn’t take no for an answer.”

Alistair says politics isn’t the full Luciana. “She’s very funny – a cool person.” And the abuse she receives? “She has a lot of strength. She won’t combat hate with hate.” Then his tone darkens. “I can’t repeat what I’d say behind closed doors.”

The first time I visit Liverpool to meet Berger, a massive cruise ship is sitting in the docks, a glitzy illustration of the regeneration of this area. The lights of smart hotels and restaurants bob in inky water, and the iconic bronze-cast Liver birds look down from above on the city’s Liver building. Arguments rage, however, about how real this development is; whether it is slick and superficial or has reached deep into the city’s deprivation. Liverpool belongs to Labour, a part of leader Jeremy Corbyn’s heartland. Even Derek Hatton, the old ex-deputy leader of Liverpool city council who was expelled for his membership of Militant, wants to finally vacate the 80s and rejoin Labour these days.

But Corbyn’s Labour party has heralded strangely intimidating times, and resulted in new attacks on Berger who is supporting Owen Smith in the current leadership election. Almost half of Labour’s 99 female MPs (including Berger) signed a letter to Corbyn deploring the party’s bullying culture and accusing him of not doing enough to stop threats against women by his supporters. “I’m very worried about the future for women in politics,” admits Berger, who joined parliament in 2010 as one of 64 new Labour MPs – 32 men and 32 women. “It’s definitely got uglier. People feel they have permission to say the most awful things.”

John Nimmo, who messaged Berger saying she would ‘get it like Jo Cox’. Photograph: Stefan Rousseau/PA

That tone has been evident in recent Labour party mayoral nomination elections across England. It was not just that there was only one female candidate – Berger – across four contests. It was the way she was treated for having the temerity to stand. Berger has kept quiet until the vote but scheduled our final meeting for the day after the result. The nomination has gone to Steve Rotheram, Corbyn’s parliamentary private secretary. Jess Phillips, Labour MP for the Birmingham Yardley, has already posted an acerbic tweet. “All the mayors can now go on an actual man date. We can make the tea.” The responses include calling Phillips “renta gob” and a “stupid woman” – which make her point even more neatly than she does.

At the mayoral hustings, Rotheram had made a virtue out of being “too nice, too ordinary, too working class and too loyal”. “Too loyal” seemed a less-than-subtle jibe at Berger, who joined the post-Brexit exodus from Corbyn’s shadow cabinet when she resigned as minister for mental health. “A difficult decision but the right thing to do,” she says. It was undoubtedly a factor in her defeat. “Especially the fact that there was a rally in the city and one of the candidates introduced the leader very publicly… I’m sure that helped! It’s not customary for the leader of the party to be seen endorsing any candidate in an internal selection but we live in a different time.” Our final meeting is to find out why: why being young, female, Jewish and anti-Corbyn is such a challenging cocktail in politics in 2016.

I was shouted at by people who should have known better, saying: ‘How dare you put yourself forward?

Berger flashes a brightly disconcerting smile. She lost but she’s fine. As a teenager, her Saturday job was in the Disney store and you can spot the pedigree: an on/off smile of blinding wattage. One of her detractors told me she found her false but, underneath the smile, Berger’s politics are hallmarked by a deep sense of sincerity and a powerful sense of direction. The smile is just her shield.

She is originally from Wembley, and her father runs a small furnishings shop where he made Tony Benn’s curtains, while her mother was a counsellor in a palliative care unit. The family was more culturally Jewish than religiously so, says Berger, though she still adheres to the main Jewish festivals. Nonetheless, she manages to make family life sound a bit like a scene from Friday Night Dinner, with her father’s party trick being a repertoire of “incredible voices”, while her mother (who wrote a hit in the French charts in the 60s) and her brother (a successful singer in Nashville) fought over use of the piano.

The family was not particularly affluent but growing up in the Thatcherite 80s, Berger knew friends who experienced real poverty and disliked the way they were treated. She developed a strong sense of social justice, basing her desire for political change on the Jewish concept of “tikkun olam” or “heal the world”. She didn’t want power. She wanted to make a difference.

Opposing force: Berger sees Jeremy Corbyn as ‘principled’ but ‘not a leader’. Photograph: Alex Telfer/The Observer

The morning of the result, she received messages of support from women who feel she has made a difference, just by seeking nomination in the current climate. One says,: “The way you were treated during the selection process by some was awful so I wanted to thank you for standing.” What was that treatment? “At the start,” she says, “I had a colleague say to me that we already had a contest with the two men, which disgusted and appalled me.”

Following the result, criticism increased. “My campaign manager and I were shouted at by people who should have known better. There was a massive sense of entitlement around the other two candidates’ teams. I was absolutely right to stand – I’d do it all again tomorrow.”

Strange that it was Berger’s experience that was constantly questioned. “The left have a problem with women,” one young (male) party member tells me, while another describes their horror at hearing Berger publicly referred to as “a young pup” by another candidate. Yet she was the only one of the three with shadow cabinet experience. She has two degrees and despite being only 35 has worked at the London stock exchange and BP, and for the Commission for Racial Equality mapping Muslim-Jewish engagement, as well as being a runner at Paramount in America and a debt collector for an American production house. (The English accent worked, apparently.) And Disney, of course.

You have to admire Berger’s courage and tenacity, particularly in the wake of fellow politician Jo Cox’s murder. “I suppose we all think we are untouchable but it means we have to take our security more seriously.” Did it frighten her? “I suppose I have been contending with issues surrounding my safety and security for years.” But what’s going on right now – why have things escalated to such ugly proportions in British politics? “Everything is just so much more polarised, particularly in the wake of Brexit. If you think about the British psyche right now, I saw doctors’ reports of increased presentation of people concerned about their mental health, for instance. Brexit was a prompt, a catalyst for uncertainty.”

To be fair, Berger believes that – unlike misogyny – antisemitism exists more out of the Labour party than in it. But she is still “disappointed” that Shami Chakrabarti’s official report into antisemitism absolved the party completely. “There [was a bit of it] that had no place there unless someone had asked for it.” Did she feel the report was manipulated? “I just didn’t believe that it was independent.” Does she believe Corbyn is manipulative as a leader? “You can’t just look at him in isolation. You have to look at the people who surround him. Incidentally, not many women!”

Corbyn, one party insider tells me, is a puppet in the middle, divided between MPs who don’t think he can lead Labour to victory and party militants who are more interested in the power of opposition than the power of government. It’s an unprecedented catch 22 with accusations of intimidation flying. Did Berger feel there was a murky side to what was happening at Westminster? “Yes, but it was more the ineptitude. I served under Ed Miliband and there was a stark contrast in terms of the professional operation and everything that happened in terms of trying to get a response.”

Labour’s women MPs after the 2010 election, including Berger, centre back row. Photograph: Tim Ireland/PA

Berger was present when Corbyn was elected candidate for the leadership. So why join his cabinet if he’s inept? “I wanted to give him a go. I didn’t know him. I have sat in cabinet meetings every week since last September and saw some of the things that have been well documented in the health team. I saw it with transport. On the day when we should have had a campaign on the increase in train fares, we had a reshuffle going on. That’s not how you take the Tory government on.”

Personally, Berger says, she gets on well with Corbyn. He’s a man of principle. “But that doesn’t make him a leader.” If Corbyn wins, can Labour win an election? “I don’t think so. In order to win, you need a united Labour party and that isn’t what we currently have.” Winning is important to Berger because it’s about changing lives. She remembers the 80s recession and her family not being able to afford a Chinese takeaway. She remembers Thatcher getting to the top and pulling the ladder away, so she makes sure she mentors a woman every year through the Fabian Women’s Network. Small changes can make big differences.

You can’t be the great niece of Manny Shinwell without having a sense of heritage about the Labour party and a sense of responsibility about its future. “Absolutely not,” she retorts smartly, when asked if the Labour party could split. She’s committed. The party is held in trust for future generations and there’s a duty to safeguard it. Not even the level of violent abuse she has experienced dents Berger’s resolve. She’s going nowhere. But she thinks Corbyn is not the best caretaker. “Ultimately,” she says, “the thousands of people I represent deserve a Labour government. They deserve not just a viable opposition but a government in waiting – and currently we are not.”