I think on the first point it was around the turn of the century.
There was a real moral panic around the time William Hague's shambolic opposition released leaflets on BOGUS ASYLUM SEEKERS and it all dated from that. At the time, the tone was seen to be in very poor taste by the vast majority and this aspect of his 2001 "campaign" was widely criticised and derided for simply being too right wing.
It's interesting and sad to see the change in a quarter of a century. The contents of that leaflet are mild compared to some of the deranged rhetoric since 2019 and prior to that the seeping poison of the hostile environment built by both Labour and Tory home secretaries.
I see it as part of the consequences of the dying out of the second world war generation- the generation that actually experienced fascism on its own skin and fought to crush it. Back at the turn of the century the vast majority of the population still hated and derided fascists- then came the BNP's electoral strategy in the first part of that decade with all it's attendant successes. The election of Derek Beackon in 1993 provoked national headlines in every newspaper, all in horrified tones; the same with Burnley at the beginning of the twenty first century, and Dagenham a little later. The blame was put on the horrible white working class for tunring xenopohobic by a middle class liberal press although as i recall the voting demographics were much more complicated and mirrored closely the self made lower middle class shop owner/ self emplyed tradesman or businessman as key to their supporter base.
Now that the generation who fought in 1939-45 are all but gone, they have been replaced by a boomer generation who in the 1960s were fed up of hearing about the sacrificies their parents made in the war, but today in the ranks of Reform UK and other weird far right sectlets almost come across as though they had fought in it. To say nothing of the younger generation whose experience of that conflict is youtube videos and games. As lived experience fades away, in a febrile time politically, the war and its central narrative in stories of Englishness / Britishness becomes a blank canvas that the far right can pour any old shit onto and pass it off as authentic.
My view on immigration is twofold. I have no concerns about people coming here and we as a couple (my wife is a non-EU European) had to negotiate the byzantine complexities of the hostile environment and pay over ten grand just so she could stay here. The level of detail, the booby traps in the forms, the finance required (new entrants for citizenship now have to pay £1500 annually towards the NHS and have NO RECOURSE TO PUBLIC FUNDS stamped on their visas) , the level of evidence required, the fingerprinting and suspicious treament at national borders by the loathsome UK Border Agency, the delays, the uncertainty, are all very stressful and wearing and we were lucky in not encountering major problems. The baffling thing for us is that the vast majority of British citizens are totally ignorant of these processes and have no idea how hard the hostile environment is. They have no clue and many simply don't believe you when you lay out the structural cruelty of the hostile environment. They think because you are in a stable (heterosexual) relationship you just get citizenship in a straightforward process and are stunned when you regale them with stories that some young children in this country think their father or mother is an ipad- becuase that's the only place they can see the, with their parents trapped in the hostile environment maze and obliged to live abroad. God knows what it's like to be an asylum seeker living on less than destitution levels in a cheap B&B somewhere.
The issue is that you cannot prevent people wanting to move for a better life. You cannot prevent people fleeing war or the consequences of climate change. The default
"fuck you and your problems, go back to where you came from" is neither humane or sustainable. This is one of the big contradiction of late neoliberalism; harmonising global currency flows to minimise tax liability yet making physical mobility from one country to another much more difficult. The one undermines the other.
On the assumption that immigration not only can't be "stopped" but also will accelerate as climate changes takes giant leaps towards making the planet unliveable, we're going to have to learn to manage immigration properly. I accept that in London and the South East population numbers are over-heated and immigration is one of the pressures on beleagured public services and local government. But, in Scotland, Wales, parts of provincial England, immigrants are actually needed to help keep public and care services ticking over and communities viable. I am in favour of admitting people via a much simpler process based on their capability to contribute to the economy, the community, or both, where they are needed. In turn the people coming here would have to accept being placed in a particular area where they are needed, which is very unlikely to be London, and to control movement requiring them to stay in- let's say- Berwick, or Elgin, or Carmarthen, for a fixed period of time, to do the jobs that are required in more remote places.
The hostile environment rests on a number of false assumptions- that people come here to scrounge off the taxpapyer, for lavish benefits, for an easy life at every else's expense. These lies need to be challenged, exposed and called out at every turn. And with those lies exposed, and the hostile environment rolled back, a new system balancing economic need and our humanitarian obligations needs to be built and supported. Humanitarian obligations will loom much lagrer as the climate emergency gets worse and worse. in this sense "Stop the Boats" and "Immigrants come here to sponge off us" are absolute poison taking us in exactly the opposite direction to where we need to go.
Honestly I'm sick of the lies, the manipulation, the desperation to believe in a parallel reality about immigration. One day we'll realisr that it's here to stay, number will continue to increase, and we have to plan to accommodate people where they are needed and support them on a journey towards becoming a full part of the communities they reside in. The vast, vast majority of immigrants want nothing from us- they come here to work and build a decent life for themselves and theiur family and don't want to take anything from us. The sooner we all realise that the better.
Lastly: acknowledging the complicity of both sides of Westminster in constructing this hateful system, much of the blame lies with Theresa May. Theresa May was always weirdly obsessed with foreigners coming here and is one of the worst sorts of Little-Englander xenophobes ever to reach the top of government. I hope in time and whilst she is still alive she is held to acount for the tens of thousands of lives she ruined, just because she's bizarrely suspicious of anyone not white, middle aged, English, and from the Home Counties.