Boris Johnson is facing mounting anger after it emerged he continued with a tour of Scotland and decided not to isolate despite a member of his team testing positive for Covid-19 on the trip. A senior government source told the Guardian the prime minister and official were “side-by-side” on several occasions and even travelled together on an RAF Voyager between Glasgow and Aberdeen, but a Downing Street spokesperson said they did not come into close contact. The civil servant, who is now isolating at a hotel in Scotland, attended an event with Johnson at a police college on Wednesday. Later that day, he and the staffer flew as part of a small No 10 contingency of about a dozen people to the next leg of Johnson’s two-day tour of Scotland – though they were said to be sat at opposite ends of a large cabin. The group were tested upon landing, and the official’s result was positive so they went into isolation. Some whose result came back negative were told to make their own way home, while others, including Johnson, finished the tour. The prime minister was then pictured meeting the business secretary, Kwasi Kwarteng, the Scottish Tory leader, Douglas Ross, and the Conservative MP Andrew Bowie. Johnson and several members of the No 10 contingent are not isolating – but a government source said “the whole lot should be”. The Downing Street spokesperson also refused to say if he had been tested since the positive case was discovered. The prime minister is spending the weekend at Chequers, meaning if he is told to stay at home it will be the second time in a month he has had to spend 10 days in his countryside grace and favour mansion. After coming into close contact with the health secretary, Sajid Javid, who tested positive for Covid in mid-July, Johnson and the chancellor, Rishi Sunak, initially resisted isolating – claiming they could avoid it by participating in a daily contact-testing pilot. However, within hours they bowed to public pressure and said they would self-isolate. Anneliese Dodds, the Labour party chair, said it was clear the prime minister “hasn’t learned anything from what happened last time he tried to cook up a reason to be above the rules everyone else has to follow”. She said: “Senior Conservatives are really taking the public for fools. This is yet another example of one rule for them and another for everyone else.” Ed Davey, the Lib Dem leader, also called on Johnson to confirm he had not been asked to isolate again. Referring to the excuse Dominic Cummings used for breaking lockdown rules last spring, Davey said of the prime minister: “If it turns out he has scorned his own government’s policy on self-isolation again, the public reaction will be Barnard Castle on steroids.” After being approached by the Guardian, a Downing Street spokesperson said: “The prime minister regularly visits communities across the UK and all aspects of visits are carried out in line with Covid guidance. The prime minister has not come into close contact with anyone who has tested positive.” Questions still remain, including over when the prime minister last tested negative, if he has the Covid contact-tracing app on his phone, and whether he wore a mask on the flight with the staffer concerned. Government guidance makes clear that in England it is “recommended and expected that passengers wear face coverings onboard aircraft”. Johnson may also have to cooperate with the test-and-trace scheme set up in England and the separate test-and-protect operation in Scotland. The rules by Public Health England say “contacts of a person who has tested positive for Covid-19 need to self-isolate at home because they are at risk of developing Covid-19 themselves in the next 10 days”, adding: “They could spread the virus to others, even before any symptoms begin.” A contact is defined as someone who has had face-to-face contact with a person who has the virus from two days before they tested positive; been within 1 metre for one minute or longer; or been within 2 metres for more than 15 minutes – either as a one-off or added up together over a day. It also includes someone who has “travelled in the same vehicle or plane as a person who has tested positive for Covid-19”, raising the chances Johnson’s flight with the staffer could yet see him forced into isolation. Though he is fully vaccinated, everyone contacted by test and trace must still quarantine. The rules will change on 16 August to allow those who are fully vaccinated to avoid isolation. Johnson faced calls to bring the date forward but resisted doing so, saying it was important people continued to follow the existing isolation rules to avoid spreading the virus. His trip to Scotland was also mired by a joke he made that Margaret Thatcher gave a “big early start” to green energy by closing coalmines, which was denounced as “unbelievably crass” by the Scottish first minister, Nicola Sturgeon.