Sky News, positive tests for Covid-19 have been reported in three of the four scientific teams at the lab.Administrative and warehouse workers at the site have also reportedly tested positive.The site was the first in the UK to officially record the new, more transmissible Covid strain back in September, which led to Tier 4 restrictions being introduced.One worker claimed there were repeated breaches of Covid safety rules at the lab, Sky News reports.The outbreak has left around 20 staff members in one 70-person lab team currently isolating, a source told the broadcaster.It comes after the UK’s Covid death toll rose by 574 on Christmas Eve to hit 69,625.A further 39,036 cases were also recorded.The lab, which was visited by Prime Minister.