The UK has seen its first death from Omicron, even as the latest variant of the coronavirus is expected to comprise 50 per cent of the cases in London by Tuesday, Prime Minister Boris Johnson said on Monday.

"Sadly yes, Omicron is producing hospitalisations and sadly at least one patient has been confirmed to have died with Omicron. So I think the idea that this is somehow a milder version of the virus, I think that's something we need to set on one side and just recognise the sheer pace at which it accelerates through the population. So the best thing we can do is all get our boosters," he said during his visit to vaccination clinic near Paddington, in west London, according to media reports.