There's not a lot of data yet on that variant's transmissibility and lethality but it has already been detected in the UK.
Thus far it doesn't seem to be as dangerous as the Brazilian P1 variant, but could be trouble just the same.
Speculation at this point to be honest.
Multiple trails of evidence pointing to it's emergence in India, and right now the UK is not restricting travel from India so the most likely scenario is that it arrived in the UK from someone who traveled to India or another country where that strain is spreading.
Is this a thing that's known to have occurred in other viruses? It seems rather unlikely compared to the chance that it came from someone asymptomatic or someone who skipped over the border controls via boat or something like that.
I'd be careful speculating over demographics. There's been a wave of violence against Asian (largely Chinese, Japanese and Korean) people in the US, believed to be caused at least in part by our former president accusing China of accidentally releasing the virus. I wouldn't want some populist to latch on to this theory and start blaming Indian people for variants.