Up to 15 MPs including the Prime Minister could be required to self-isolate after coming into contact with a person who tested positive for coronavirus, The Telegraph understands.
Lee Anderson, the MP for Ashfield, tested positive for Covid-19 on Sunday after noticing symptoms last Friday morning.
He attended a meeting in Downing Street with other Northern Tory MPs and Boris Johnson on Thursday, and sat in the chamber for a debate on Wednesday during a period when he is thought to have been infectious.
Nine MPs, including Mr Anderson and Mr Johnson, have already announced that they will self-isolate, but several more are thought to have been contacted by NHS Test and Trace.
Jacob Young, Maria Miller, Lia Nici, Brendan Clarke-Smith, Andy Carter, Katherine Fletcher and Chris Clarkson have said they will now isolate.
A Conservative source said six MPs were meeting Mr Johnson as part of the Prime Minister’s “reset”, an attempt to secure the support of his backbenchers amid turmoil in Downing Street.
After Mr Anderson tested positive he was advised by the Tory whips’ office to contact Parliament’s internal test and trace system, The Telegraph understands.
The MP appeared in a Parliamentary debate on Remembrance Wednesday afternoon, where he sat near Ms Miller, a former Conservative Cabinet minister. He and his wife, who is clinically vulnerable, are now self-isolating.