Boris Johnson announces tightening of Covid rules after Omicron reaches UK

The Omicron variant of coronavirus has been detected in the UK (Leon Neal/PA)

In the UK, mask rules will be mandatory in shops and on public transport, Omicron contacts will have to self-isolate and new arrivals will have to quarantine until they test negative for coronavirus after two cases of the concerning new Omicron variant were detected.

Boris Johnson warned the new variant could reduce the effectiveness of vaccines, as he announced a strengthening of England’s rules at a Downing Street press conference, after the infections were identified in Nottingham and Brentwood in Essex.