An MP of the Scottish National Party who tested positive for coronavirus, attended the House of Commons on Wednesday and later travelled on public transport from London to Edinburgh faced persistent calls to resign on Friday.

Margaret Ferrier, MP from Rutherglen and Hamilton West, has been suspended by her party. Nicola Sturgeon, party leader and Scotland’s First Minister, said she had spoken to Ferrier and asked her to step down as MP. She also faced strong criticism from speaker Lindsay Hoyle.

Ferrier’s actions revived debate about everyone, irrespective of position, following law and quarantine rules after evidence emerged of former Labour leader Jeremy Corbyn and Stanley Johnson, father of Prime Minister Boris Johnson, not obeying such rules.

Ian Blackford, SNP leader in Westminster, said Ferrier had broken the law and should therefore reflect very carefully on whether she can continue as a Member of Parliament for her constituents. “Nobody is above the law, nobody is above the regulations…I am calling on Margaret to do the right thing.”

Ferrier, 60, apologised for her behaviour in a statement: “I apologise unreservedly for breaching Covid-19 restrictions by travelling this week when I shouldn’t have. There is no excuse for my actions.”

“I deeply regret my actions. I take full responsibility and I would urge everyone not to make the same mistakes that I have, and do all they can to help limit the spread of Covid-19”, she added.

Ferrier spoke for four minutes in the House of Commons in person. The House has been functioning under strict Covid-secure conditions that include few MPs present, with others joining debates through video link.

Ferrier’s actions are now a subject of police investigation in London and Scotland, Hoyle said. It could result in a £4,000 fine recently announced by the government for those breaching quarantine regulations.