Immigrants are a fantastic pool of talent. There's a reason why so many businesses in my area (particularly in catering and supermarkets) are mainly staffed by Eastern Europeans and Asian immigrants, rather than white English people, and that's because they offer employers better value for money.
Yes, better value for money because they will work 12 hour days and 6 hour weeks and be too scared to ask for overtime. Won't take their legal entitlement for breaks or worry about expensive inconveniences like safety equipment. Or demand that their wages are improved to reflect their hard work. And they'll take jobs with limited rights, zero hour contracts or dubious 'self employment' and work on baseis which allow their employers to avoid inconveniences like maternity pay. They don't ask for anything like flexibility or regular hours or a guaranteed wage.
British workers with their awful expectations of rights, proper wages and basic respect are terrible value.
And waiting tables and stacking shelves is not a 'talent', they're basic skills we don't need to import.
long term unemployed in the UK are often beset by problems which make them unattractive to employers. They are often poorly educated, have poor physical or mental health, or family lives so complicated (and unsupported) that they simply can't hold down a job.
Oh heaven forbid that employers should support and keep on employees with health problems or families.
It would be awful for employers and for the economy if that talent pool was to dry up because of severe restrictions on immigration.
But great for employees whose labour would become valuable again.
I'm not sure if your left wing or not, but these are pretty familiar left wing arguments these days and it's tragic that the left wing has come to a point where it will argue that everything it once stood for is unnecessary and undesirable just to defend the sacred cow of migration.
Because of course poor people and the unskilled don't matter unless they come with some sort of exotic back story to get excited about. Just chuck 'me on benefits for a subsistence life because they're 'bad value'. Work should pay enough to raise families without recourse to benefits apart from the very bottom strata. But it's not even possible on fairly decent or even average wages these days.