I remember the first time I was called “Paki”. It was 1978 at primary school in Ealing, west London, now my constituency. I was quite startled. My playground tormentor had to explain the etymology of the term to me. I retorted:“Actually, East Pakistan has been liberated into Bangladesh since 1971; it’s an independent country”, which shut him up.

I was born in Hammersmith the year after Bangladeshi independence and recall the racism of old. In those days, “the host community” saw the likes of me and the two kids in our school with turbans (brothers) as “Asian” – the shorthand “Paki” overlooking different nationalities. The subtitles of religion had not reared their head. The Satanic Verses and 9/11 changed that when the badge “Don’t freak, I’m a Sikh” was produced, signalling a disaggregation of Asians. Race broke down into religion.

When asked on TV about Boris Johnson’s recent calculated outburst, I found myself doing his voice and gestures. “It was like being in room with him,” Krishnan Guru-Murthy later commented on Twitter. But I fear that the lovable rogue act is wearing somewhat thin. He cannot be trusted: his flippant words endangered Nazanin Zaghari-Ratcliffe’s life; he wrote two columns on staying in Europe (for and against) and plumped for the latter, on deciding it played better among the Tory membership for his leadership bid; and, as my impression hinted, his private life has been “colourful”. I don’t have a vote in the contest and am not a burqa fan, but in his not very veiled attempt to assume the crown, the damage is already done. It would be a tragedy if he became PM through leveraging hatred against the most visibly different UK community who are already vulnerable and under attack.

It’s not enough to excuse his likening of burqa-clad women to letterboxes and bank robbers as eccentricity when it fuels Islamophobia. As an MP, you’re de facto a magnet for abuse – for me, usually with a Muslim twist, sometimes for speaking about justice for Palestinians, or even the dangers of leaving the EU. This spring, I received an Islamophobic package, containing a “Punish a Muslim Day” warning letter doused in a mystery substance. It resulted in police cordoning off my office as a crime scene and one of my staff being taken to hospital for examination – it was the week after the Salisbury attack. Every time a pronouncement like this is made, women have hijabs ripped off, grandfathers are attacked on the way to mosque and mosques have pigs’ heads left on their doorsteps. Such flippancy has consequences.

At the most dangerously rightward tilting moment in politics since the 1930s, Johnson’s intervention is fuelling the flames of the deplorable rise of all forms of hate crime in our society. With the ransacking of a radical bookshop and rebirth of rightwing thug Stephen Yaxley Lennon as folk hero Tommy Robinson, anti-racists should stand as one against Islamophobia, homophobia and antisemitism. The climate we have in our post-referendum divided nation has disinhibited the hate-speakers. The fate of my late friend and colleague Jo Cox, murdered in cold blood when doing something I undertake weekly – my advice surgery – is a reminder of where these sentiments can lead.

In the meantime, I have no idea what became of my infant school abuser. I’m not going be pursuing him for an apology 40 years on, but wherever he is I hope he’s a reformed character. Sadly, all the evidence on the ground is that racism is taking a more pernicious tone and Boris Johnson has just made it worse.

• Rupa Huq is Labour MP for Ealing Central and Acton