Boris Johnson appeared maskless during a visit to a hospital on Monday despite fears that Covid is spreading around parliament, with 114 people catching the virus on the Palace of Westminster estate in the past month. The prime minister was seen walking along a corridor in Hexham hospital in Northumberland and posing for pictures alongside medical staff who donned light blue face coverings. Johnson was seen elbow-bumping and wearing a mask at some other points. No 10 said Johnson followed the guidelines set by the local NHS trust. A source said Johnson had just left a meeting where he was speaking, was not in a clinical area, and put a mask on shortly afterwards. Safety measures have been gradually reintroduced to the House of Commons, and more Tory MPs have begun wearing face coverings in the chamber, though some frontbenchers – including the Commons leader, Jacob Rees-Mogg, and the chief whip, Mark Spencer – remained maskless during a debate on Monday. George Freeman said he had a “bad attack” of coronavirus last week and faced difficulty breathing, so had been confined to bed on doctors’ orders. About five Labour MPs were said to be isolating with the virus, with the figure rumoured to be slightly higher on the Conservative side. The prime minister was accused by opposition MPs of running scared from an emergency debate in parliament about his botched attempt last week to save a Tory colleague, Owen Paterson, from suspension for breaking lobbying rules. Johnson took a train back to London from Northumberland, leaving him unable to attend the debate. A Tory aide “noted with disdain” that last week he flew by private jet back from the Cop26 climate change conference in Glasgow to make a dinner reservation at the Garrick Club with a close ally of Paterson’s. Some politicians have been concerned by the spread of Covid in parliament for months. An internal memo seen by the Guardian from authorities sent to staff on Monday said the Covid risk for those working in Westminster “had increased, and swift action was necessary as a result”. It confirmed there were 114 cases “with links to the estate” found between 4 October and 5 November. Further restrictions for parliamentary workers could be introduced following a meeting of the Commons commission later this week. Jenny Jones, a Green peer, said the Lords had been better at maintaining Covid measures than the Commons. However, she said, she had complained that ministers’ aides still came into the chamber maskless. Jones told the Guardian the government remained “arrogant and careless” on the issue. Mike Clancy, general secretary of the Prospect union, which represents professionals including parliamentary staffers, said: “The number of cases directly linked to the estate is worrying but we’ve been warning for some time that poor enforcement or observation of the rules, particularly amongst MPs, would result in a spike in infections. We will be checking the numbers carefully in the coming days and it may be that we need to recommend stronger measures than we have currently. In the meantime everyone should be wearing a mask and practising social distancing to protect themselves and parliament staff. MPs should be leading by example on this.”