The Roman Catholic church in Glasgow has expressed its “disappointment” after it was reported that the SNP MP Margaret Ferrier attended a church service and gave a reading to the congregation the day after she took a test for coronavirus. Ferrier has faced a barrage of criticism and calls for her to stand down after revealing last Thursday that she travelled to London and spoke in the Commons while awaiting the result of a coronavirus test, then returned by train from London to Scotland after testing positive. The Daily Record newspaper reported on Tuesday morning that Ferrier attended a mass at St Mungo’s Church in Townhead, Glasgow, on Sunday 27 September, the day after she took the test. She is also believed to have given a Bible reading from the altar. The MP’s social media posts also show that she visited a gift shop, a beauty salon and a leisure centre in her constituency on Saturday 26 September, the day she developed symptoms and took the test. Responding to the report, the archdiocese of Glasgow said: “For the good of the whole community, it is important that anyone who is required to self-isolate does so in accordance with the government’s guidance, so anyone in that situation should not attend mass. It is disappointing if this has not happened but we would like to reassure people that we fulfil all the government and church guidelines.” The church’s website states public mass is limited to 50 people and those who are shielding, self-isolating or feel unwell should not not attend. The SNP moved quickly to suspend Ferrier on Thursday night, with the party leader, Nicola Sturgeon, continuing to call on her former colleague to “do the right thing” at her daily briefing on Monday, while constituents and colleagues have expressed their disappointment and anger. The Rutherglen Reformer published a furious open letter to Ferrier, the local MP, on the front page of Wednesday’s edition, calling for her to resign “before you become a social pariah and not just a political one”. The Reformer said it has been inundated with messages from angry readers. But friends are believed to be encouraging Ferrier to take time before reaching her decision, pointing to other former SNP MPs who stayed on as independents as well as the former finance minister Derek Mackay, who remains an MSP eight months after he was suspended following reports that he sent inappropriate messages to a 16-year-old boy on social media. Writing in the National on Monday, the former MP George Kerevan claimed Ferrier was a victim of a trial by media fuelled by “virtue signallers” in his own party. Supporters of Ferrier’s also pointed to an email issued by parliamentary authorities to MPs and other workers in the parliamentary estate on Monday as evidence Ferrier may not have fallen foul of the rules when she took a train back to Glasgow. It advised workers in the Palace of Westminster that if they develop symptoms of Covid or receive a positive test result they should make their way home immediately and “use private transport to travel whenever possible” but added they could use “public transport wearing a face covering there is no alternative”. Opposition parties have questioned why the SNP has not expelled Ferrier. Also on Monday, the Scottish Conservative leader, Douglas Ross, said: “If the SNP expect the public to keep making sacrifices, they’ve got to take action; warm words won’t cut it. It’s baffling that they’re still dragging their heels. Margaret Ferrier knowingly went on public transport with Covid, recklessly risking the lives of others. This is not a trial by media. It’s a trial by her own sheer stupidity and there is no doubt she’s guilty, so the SNP must expel her.” As well as the police, Ferrier has referred herself to the Commons standards commissioner but it is not expected to conclude its investigation for some time. The shortest investigation it has undertaken took two weeks. If the standards investigation results in suspension from the house for 10 days or more, this would trigger a recall petition, which would allow her constituents to decide whether they want a byelection. On Wednesday afternoon, the Labour leader, Keir Starmer, will host an online Call Keir session with voters in Ferrier’s constituency. Ferrier’s office has been approached for comment.