Alok Sharma, the business secretary, has been tested for coronavirus after feeling unwell while delivering a statement in the House of Commons.
The cabinet minister has gone home to self-isolate following his appearance at the dispatch box earlier on Wednesday.
The parliamentary authorities are understood to have given the area a deep clean and MPs were at the time sitting at least two metres apart. “This was done as a precaution,” a House of Commons source said.
However, his suspected illness is likely to cause concern about the government’s decision to bring back parliament in its physical form, after weeks of allowing MPs to attend remotely via video link.
Many MPs have protested against the new arrangements, which have resulted in them queueing around the parliamentary estate while complying with the two-metre physical distancing rules in order to vote.
Observers noticed that Sharma appeared unwell and to be sweating profusely while he spoke about the corporate insolvency and governance bill in the Commons.
A spokeswoman for the business secretary said: “Alok Sharma began feeling unwell when in the chamber delivering the second reading of the corporate governance and insolvency bill. In line with guidance he has been tested for coronavirus and is returning home to self-isolate.”
If Sharma does test positive, it will be an early trial of the government’s new contact tracing system. Other MPs and officials who have been in close contact with him will be tested and could be asked to self-isolate.
During the debate, after Sharma was seen wiping his face with a handkerchief several times, his Labour shadow, Ed Miliband, passed him a glass of water. Sharma also appeared sweaty and sounded hoarse on Tuesday, according to one fellow MP, when he voted to abolish hybrid parliamentary measures.
During one vote, the minister voted straight after the culture secretary, Oliver Dowden, and immediately before the Labour MP Stephen Kinnock. He was also one of a few ministers who attended full cabinet, a source said.
Kirsty Blackman, SNP deputy leader in Westminster, sent her best wishes to Sharma but said: “[It] does, however, demonstrate just how ridiculous and irresponsible the Tory government’s decision to end virtual participation in parliament was. They must now rectify this serious mistake and reintroduce hybrid proceedings without delay.”
Lisa Nandy, Labour’s shadow foreign secretary, said the development was “just awful”, adding: “The government stopped MPs from working from home and asked us to return to a building where social distancing is impossible. MPs are travelling home to every part of the country tonight. Reckless doesn’t even begin to describe it.”
Digital voting in the Commons was ended on Tuesday after MPs approved a government motion introduced by the leader of the house, Jacob Rees-Mogg, despite widespread objections.
Senior Conservatives, opposition groups, unions and the equalities watchdog raised concerns that the move would prevent many MPs, particularly the elderly and vulnerable members who are shielding, from being able to vote.
The Labour MP Karl Turner said he had asked the Health and Safety Executive to conduct an urgent risk assessment of working conditions in parliament.
He said MPs having to “huddle together” on escalators on the parliamentary estate while lining up to vote were among a number of “unsafe practices”.
A string of cabinet ministers and senior officials have come down with coronavirus since the start of the pandemic, including Boris Johnson, who was treated in intensive care.
Matt Hancock, the health secretary, Chris Whitty, the chief medical adviser, Mark Sedwill, the cabinet secretary, Dominic Cummings, the senior No 10 adviser, and Ben Wallace, the defence secretary, were also all unwell with coronavirus in late March or early April.
The first MP to fall ill with the virus was Nadine Dorries, a health minister, who tested positive in March.
A House of Commons spokesperson said: “The house’s priority is to ensure that those on the estate are safe while business is facilitated. We have closely followed guidance from PHE on action to take following a suspected case of Covid on site, including additional cleaning. Our risk assessment outlines the measures we have already put in place to reduce the risk of transmission in parliament.”